Print
An updated checklist of the bees (Hymenoptera, Apoidea, Anthophila) of Pennsylvania, United States of America
expand article infoShelby Kerrin Kilpatrick, Jason Gibbs§, Martin M. Mikulas|, Sven-Erik Spichiger|#, Nancy Ostiguy, David J. Biddinger, Margarita M. Lopez-Uribe
‡ Pennsylvania State University, Pennsylvania, United States of America
§ University of Manitoba, Winnipeg, Canada
| Pennsylvania Department of Agriculture, Harrisburg, United States of America
¶ USDA, Animal and Plant Health Inspection Service, Lancaster, United States of America
# Washington State Department of Agriculture, Olympia, United States of America
Open Access

Abstract

Checklists provide information about the species found in a defined region and serve as baselines for detecting species range expansions, contractions, or introductions. Bees are a diverse and important group of insect pollinators. Although some bee populations are declining, these patterns are difficult to document and generalize due to a lack of long-term studies for most localities. Documenting the diversity of wild bee communities is critical for assessing pollination services, community ecology, and geographical and temporal changes in distribution and density. Here, an updated checklist of the bees of the Commonwealth of Pennsylvania, USA, is presented. Since the first checklist was published (2010; 372 species), thousands of additional specimens from the state have been collected and databased, new species have been described in the region, and the taxonomic status of some species have changed. Specimen data from insect collections, databases, scientific literature, and unpublished records were compared to the original checklist. Seventy-nine new state species records – including 49 first-time reports – representing five of the six bee families in North America, were documented resulting in a total of at least 437 bee species reported from Pennsylvania. We highlight new county records and species persistence details. Our list includes a total of 23 exotic species and at least five species of conservation concern. Lists of species excluded from the state checklist and species anticipated to occur in Pennsylvania are also included. This checklist provides baseline data for researchers and the public. The benefits of insect collections, specimen databases, determination and voucher labels, and georeferencing to biodiversity studies and other aspects of biological research are also discussed.

Keywords

Aculeata, adventive species, Andrenidae, Apidae, biodiversity, check list, Colletidae, conservation, distribution, faunal records, Halictidae, new records, Megachilidae, Melittidae, persistence, phenology, pollinators

Introduction

Bees (Hymenoptera: Apoidea: Anthophila) represent a fascinating and diverse group of insects. World-wide, there are at least 20,473 species of bees and, of these, 5,227 species are recorded from North America (Ascher and Pickering 2020). The majority of these bee species are native, but at least 45 species have been introduced to the continent since 1620 (Russo 2016; Gibbs and Dathe 2017; Martins et al. 2017; Normandin et al. 2017; USGS Native Bee Laboratory 2019). Because of their ecologically important role as pollinators of flowering plants in natural ecosystems and agricultural areas, maintaining wild bee species diversity is critical for crop pollination and ecosystem function (Genung et al. 2017; Winfree et al. 2008; Winfree et al. 2018; Grab et al. 2019).

Overwhelming evidence of declines in managed and wild bee populations has emphasized the need for a better understanding of bee diversity across different geographic areas (e.g., Potts et al. 2010b; Colla et al. 2012; Bartomeus et al. 2013). Despite extensive research efforts, our understanding of the status of most native bee species remains deficient (Cane and Tepedino 2001; Potts et al. 2010a; Koh et al. 2016; Meiners et al. 2019). It is challenging to assess the status of many species due to a lack of comparable historical and long-term datasets. In the past 140 years, non-Apis and non-Bombus bee species richness declines measured 15% in the northeastern United States (Bartomeus et al. 2013). Recent surveys revealed that ~5% of the eastern North American species had not been documented between 1990 and 2009, though the exact reason(s) for their absence in collections remains unconfirmed (Colla et al. 2012). These findings in bees reflect the larger issue of global insect decline, most recently reviewed by Montgomery et al. (2019).

Checklists serve as baselines, helping fill the lack of knowledge of species’ distributions, taxonomic classifications, and biodiversity of a region. They may also contribute details on the phenology, persistence, and other biological aspects of species. Checklists can be used to detect range shifts in both native and non-native species over time, and to identify under-surveyed localities and seasonalities (e.g., Dibble et al. 2017; Gibbs et al. 2017a). This information can contribute to establishing long-term monitoring programs (Berenbaum et al. 2007; LeBuhn et al. 2013). Repeated surveys, coupled with long-term monitoring of bee biodiversity, community composition, and population dynamics over time, can provide data to establish conservation strategies and priorities (Berenbaum et al. 2007; LeBuhn et al. 2013; Koh et al. 2016).

Taxonomic studies of bees in the eastern United States have documented some of the biodiversity in the Commonwealth of Pennsylvania (PA), USA (Cockerell 1908; Stephen 1954; Mitchell 1960, 1962; Ordway 1966; Shinn 1967; Roberts 1972; Daly 1973; LaBerge 1969, 1971, 1973, 1977, 1980, 1985, 1987, 1989; LaBerge and Bouseman 1970; LaBerge and Ribble 1972, 1975; Milliron 1973a; Baker 1975; Timberlake 1975; Svensson et al. 1977; Bouseman and LaBerge 1978; McGinley 1986, 2003; Broemeling 1988). Donovall and vanEngelsdorp (2010) published the first checklist of bees in Pennsylvania, reporting 372 species from 13,076 specimens located in 20 collections. Since then, a number of crop pollination studies and citizen science projects have been done in the state (e.g., DeBarros 2010; Sidhu 2013; studies cited in Table 1). In addition, the Pennsylvania Department of Agriculture (PDA) has surveyed bees nearly annually since 2005 (Donovall and vanEngelsdorp 2010; Karen Roccasecca, pers. comm.) and bycatch from PDA invasive pest insect monitoring traps also commonly includes bees (Mikulas and Barringer 2018). As a result, thousands of bee specimens from across the state have been collected, identified, and documented in collection databases and research publications.

Table 1.

Information about the bee specimen databases examined for this study. Database names, locations of the specimen material, the total numbers of records used, the names of people who identified material, and the names of people who provided database files/access are presented.

Database Name Location(s) of Specimen Material Total # of specimen records used Primary Identifiers Obtained from Supplemental material #
Bartomeus et al. 2013 American Museum of Natural History, University of Connecticut, Cornell University, Rutgers University, Connecticut Agricultural Station, University of New Hampshire, University of Massachusetts, Vermont State Bee Database, New York State Museum, Bohart Museum of Entomology (University of California, Davis) 537 J.S. Ascher, R.W. Brooks, E.L. Bzdyk, B. Coelho, Daly, L. Day, N.B. DeBarros, S. Droege, G.C. Eickwort, J. Gibbs, R.S. Jacobson, Bouseman & LaBerge, W.E. LaBerge, R.B. Miller, T.B. Mitchell, D.W. Ribble, L. Richardson, M.G. Rightmyer, R.B. Roberts, G. Sandhouse, R.R. Snelling, R.W. Thorp, Viereck Bartomeus et al. (2013) 2
Biddinger Laboratory Database [includes data from Shugrue (2016) and Gibbs et al. (2017b)] Penn State University Fruit Research and Extension Center, Biglerville, PA (PSUB); Frost Entomological Museum, Department of Entomology, Pennsylvania State University, University Park, PA (PSUC) 96,382 D. Biddinger, J. Gibbs, R. Jean, K. Wright Kathryn Wholaver, pers. comm. 3
Droege Database United State Geological Survey (USGS) Patuxent Wildlife Research Center, Laurel, MD 1,139 J. Ascher, S. Droege, S. Rehan Sam Droege, pers. comm. 4
Integrated Crop Pollination (ICP) Project: Fleischer Laboratory Database [includes data from McGrady et al. (2019)] Frost Entomological Museum, Department of Entomology, Pennsylvania State University, University Park, PA (PSUC) 1,176 S. Droege, J. Gibbs, R. Jean, D. Roberts, K. Watrous N/A 5
López-Uribe Laboratory Database [includes 2008 Pennsylvania Department of Agriculture survey material] López-Uribe Laboratory, Department of Entomology, Pennsylvania State University, University Park, PA 3,417 N.D. Amon, J. Baker, S. Burrows, L.R. Donovall, S. Droege, K.E. Ellis, S.K. Kilpatrick, M.M. Mikulas, R. Snyder N/A 6
Winfree Laboratory Database [includes data from Winfree et al. 2008] Winfree Laboratory, Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ 17,804 J. Ascher, S. Droege, J. Gibbs, T. Griswold, T. Harrison, M. Rightmyer Rachel Winfree, pers. comm. 7
Mahan et al., in prep [Utility Rights-of-way at State Game Lands 33 and Green Lane Research & Demonstration Areas; https://sites.psu.edu/transmissionlineecology/] Frost Entomological Museum, Department of Entomology, Pennsylvania State University, University Park, PA (PSUC) 2,614 S. Droege, D. Roberts, L. Russo, H. Stout Carolyn Mahan and Hannah Stout, pers. comm. 8
Choate et al. 2018 [includes full data from Choate et al. (2018)] Choate Laboratory, Department of Environmental Science & Sustainability, Allegheny College, Meadville, PA 1,520 S. Droege, P.L. Hickman, E.A. Moretti Beth Choate, pers. comm. 9

This study updates the taxonomy of species listed in Donovall and vanEngelsdorp (2010), resolves dubious records reported in Donovall and vanEngelsdorp (2010), and reports additional Pennsylvanian bee species data. We present new records at state and county levels, distribution data at the county level, collection date ranges, and the most recent year of collection or observation for each species. Additionally, we discuss the natural history of Pennsylvania’s bee biodiversity, the value of checklists, and the importance of repeatable taxonomy, collections, and voucher material to faunistic studies and knowledge.

Methods

Baseline Pennsylvania bee checklist data

We transcribed the list of Pennsylvanian bee species and their county, dates of collection, most recent year of collection records, and all other information from Donovall and vanEngelsdorp (2010) (Suppl. material 1). In addition, species’ taxonomy was updated as necessary following recent revisions. This document provided a baseline to which new data could be compared to information reported in the previous checklist.

The individual specimens examined for the previous checklist were not traceable due to a lack of voucher/accession numbers or another way to reliably identify the physical material that was deposited/returned to the collections after their study. A spreadsheet that Donovall and vanEngelsdorp had used to record some of the data for their checklist was obtained via personal communications with both authors and Emily Agar (University of Guelph, Ontario, Canada). A subset of the bee species records within the spreadsheet, using their specimen data in place of voucher identifiers, were targeted for verification based on the proximity and accessibility of collections they were housed at. This included material in the following collections: Department of Entomology, Academy of Natural Sciences, Philadelphia, PA (ANSP), Section of Insects and Spiders, Carnegie Museum of Natural History, Pittsburg, PA (CMNH = ICCM), and the Pennsylvania Department of Agriculture Arthropod Collection, Bureau of Plant Industry, Pennsylvania Department of Agriculture, Harrisburg, PA (PADA). Specimens at the PADA collection were also examined for new records. As not all of the PADA specimens listed in the spreadsheet were present in the PADA collection and material at the other collections was difficult to trace, we used new data to verify previously reported species records. Furthermore, the full details for two records were not available in the spreadsheet: “USNM 1” for Colletes americanus Cresson, 1868 and “PADA 15” for Osmia cornifrons (Radoszkowski, 1887). Specifically, Pennsylvanian C. americanus specimens from the collection suggested by the codon and number was not present and, in the case of O. cornifrons, the species was absent from the spreadsheet. Thus, the full specimen records indicated by these codes could not be verified and the data was removed from the checklist. All other data published in Donovall and vanEngelsdorp (2010) was unable to be fully verified and is reprinted here with this caveat.

Specimen database review

Databases of bee specimens collected in Pennsylvania and identified by experts were primarily obtained via personal communications from eight sources between Summer 2017 and Fall 2019 (Table 1). Only species identified to a single species-level name were used; specimen records with no names and no data, identified to more than one species name (e.g., Ceratina dupla sensu lato, Hylaeus affinis/modestus), or with taxonomic uncertainty (containing terms such as “maybe”, “like”, “close to”, “cf” in their name or a notes section), were excluded. We also excluded 17 specimen records that were identified to species-level. These records warrented verification of the specimens’ identities, but we were unable to examine them of as part of this study. County-record data for specimens with no county given in the database were confirmed via personal communications with the database manager(s) or georeferenced using Google Earth Pro (version 7.3.2.5776 (64-bit); Table 1). Julian dates in Bartomeus et al. (2013) were converted to calendar dates using the DATE function in Microsoft Excel (version 16.16.15; Table 1). Individual specimen records in each database were compared to the previously published data for bee species recorded in Pennsylvania (Donovall and vanEngelsdorp 2010). For specimens without a determiner listed in the database, we treated them as if they were identified by at least one of the other experts associated with the collection’s material, but that these specimens did not have determinationlabels applied as is sometimes common when specimens are identified; not all specimens may bear determination labels by the end of the process and are thus databased without a determiner listed.

It is noted that Donovall and vanEngelsdorp (2010) used material deposited at the Penn State University Fruit Research and Extension Center, Biglerville, PA (PSUB) in their manuscript. However, as it was impossible to determine specifically what specimen records they reviewed/reported, we used all of the specimen records available. Additionally, some of the specimen records in PSUB were also part of the Integrated Crop Pollination (ICP) Project database (Table 1). To avoid duplication of records, only non-PSUB data from the ICP database was reported while the PSUB database was used in full. A total of 124,589 specimen records from databases were used (Table 1).

Literature review

We examined several literature sources that contributed to the first list of species in Pennsylvania: Mitchell (1960, 1962), LaBerge (1985), Timberlake (1975), and McGinley (2003). Other literature cited by Donovall and vanEngelsdorp (2010) as treating Pennsylvanian bee fauna was also examined to verify record information (Ordway 1966; Shinn 1967; LaBerge and Bouseman 1970; LaBerge and Ribble 1972; Roberts 1972; Daly 1973; Milliron 1973a; Baker 1975; LaBerge 1973, 1977, 1980, 1987; Bouseman and LaBerge 1978; McGinley 1986; Broemeling 1988). We also reviewed other scientific literature, with a focus on bee studies performed in Pennsylvania, the northeastern United States, or on Pennsylvanian taxa since 2010, for new species and details for inclusion in our updated checklist (Cockerell 1908; Swenk 1915; Stephen 1954; LaBerge 1969, 1971, 1989; LaBerge and Ribble 1975; Svensson et al. 1977; Schwarz and Gusenleitner 2004; Matteson et al. 2008; Rightmyer 2008; Gibbs 2009, 2010, 2011, 2012; DeBarros 2010; Droege et al. 2010; Rehan and Sheffield 2011; Gibbs et al. 2013; Sidhu 2013; Gibbs and Dathe 2017; Onuferko 2017, 2018; Mikulas and Barringer 2018). We compiled 1,283 specimen records from these sources (Suppl. material 10). County geography was verified for records as feasible using Google Earth Pro (version 7.3.2.5776 (64-bit)). There were only six cases in which a specific locality name was available, but county-level geography was impossible to assign with certainty (see comments in Suppl. material 10). Dates ranges were inferred from methods sections as feasible, though these are not included in the checklist if they did not represent a single collecting event (as in DeBarros 2010; Suppl. material 10). Furthermore, year of collection ranges from Sidhu (2013) are only reported in our checklist if they represented either the most recent year(s) of collection (n = 1) or the only known year(s) of collection for a species (n = 2) (Suppl. material 1, 10). Specimen data from Winfree et al. (2008), Shruge (2016), Gibbs et al. (2017b), Choate et al. (2018), and McGrady et al. (2019) were not included in the literature review as their data were reviewed in databases (Table 1). Reports of species or specimens inferred from range maps without data points, generalized distribution statements, tentative identifications, and observation-based records in the reviewed literature were not compiled and are thus not presented; they are considered unverifiable until either a specimen from Pennsylvania is confirmed to exist or specimens’ identities are fully confirmed.

Several of the papers reviewed did not provide full data for the specimens examined or collected. The full data for some of these (Daly 1973; McGinley 1986; DeBarros 2010; Sidhu 2013) was either stated or seemed likely to be available based on the text. The appropriate personnel at the institutions as assumed or indicated by each author were contacted in an attempt to verify complete collecting events. The availability of Daly’s (1973) and DeBarros’s (2010) data remains unknown. McGinley’s (1986) specimen data was not available from the Smithsonian Institution Archives (Ellen Alers, pers. comm.) or U.S. National Entomological Collection (USNM) / Department of Entomology (Floyd Shockley, pers. comm.). McGinley is in the process of locating these records to resolve the discrepancy (Ron McGinley, pers. comm.). In the case of Sidhu (2010), the records that were expected to be in the Frost Entomological Museum’s holdings were not available, but an additional data sheet was (Andy Deans, pers. comm.).

Additional records

State and county records were haphazardly added to the checklist as we became aware of them and they were verified. A total of four specimens, from PSUB, Rosemary Malfi Insect Collection, and Emily Erickson [now deposited in the Bee Inventory and Monitoring Lab (BIML)], were examined and their identities confirmed for inclusion in the checklist (Suppl. material 11). Other specimen records came from the Department of Entomology Collection, American Museum of Natural History, New York, New York (AMNH) available on Discover Life (http://discoverlife.org) and reliable records on BugGuide, typically identified by J.S. Ascher (http://bugguide.net) – based either on a specimen deposited in a collection or with clear archived images accompanying the occurrence record. We also systematically retrieved records from both BugGuide and iNaturalist (https://www.inaturalist.org/) on 10 November 2019 to ensure no species were missing from our checklist, and present these as supplemental records (Suppl. materials 1217). Specimen data available on GBIF.org were retrieved on 07 January 2020 (GBIF Occurrence Download https://doi.org/10.15468/dl.wghcks) and reviewed for records identified by known bee experts. The BugGuide, iNaturalist, and GBIF records that are not presented within the checklist are not included in the species data for the state, and are not represented in the tables and figures.

Taxonomy

We updated species names applied in earlier records to match modern taxonomic understanding, agree with the gender of their genus name (e.g., some Melissodes Latreille), and reflect their status as nouns (e.g., some Lasioglossum Curtis). We follow Michener (2007) with exceptions based on more recent studies. For Lasioglossum subgenera we followed Gibbs et al. (2013), and we used an inclusive Eucera Scopoli based on Dorchin et al. (2018) that treats Cemolobus Robertson and Peponapis Robertson as subgenera. For clarity, we also present a list of species names included in the previous checklist, which are not included in our results due to recent taxonomic changes or verification of Donovall and vanEngelsdorp’s (2010) original intent:

Anthophora plumipes (Pallas, 1772): Černá et al. (2017) provide evidence that A. plumipes and A. villosula Smith, 1854 are distinct species, and that A. villosula was the species introduced to North America.

Epeolus lanhami Mitchell, 1962: Onuferko (2017) synonomized this name with Epeolus americanus (Cresson, 1878).

Nomada 077ensis Cockerell: This entry was intended to be Nomada lehighensis Cockerell, 1903 based on Donovall and vanEngelsdorp’s (2010) original notes.

Nomada bishoppi (Cockerell, 1911): Schwarz and Gusenleitner (2004) synonomized this name with Nomada imbricata Smith, 1854.

Nomada inepta Mitchell, 1962: This name is a synonym of Nomada gracilis Cresson, 1863 based on Sheffield et al. (2009).

Andrena irana Cockerell, 1929: LaBerge and Bouseman (1977) synonomized this name with Andrena (Scaphandrena) nigerrima Casad, 1896. Note that this record is well outside the known range of the species, but could not be verified and has been removed from the state checklist.

Lasioglossum (Dialictus) rohweri (Ellis, 1915): Gibbs (2010) synonomized this name with Lasioglossum (Dialictus) versatum (Robertson, 1902).

Lasioglossum (Evylaeus) divergens (Lovell, 1905): Gibbs et al. (2013) synonymized this name with Lasioglossum (Hemihalictus) macoupinense (Robertson, 1895).

Lasioglossum (Dialictus) apertum (Sandhouse, 1924): Gibbs (2010) synonymized this name with Lasioglossum (Dialictus) versatum (Robertson, 1902).

Lasioglossum (Dialictus) atlanticum (Mitchell, 1960): Gibbs (2012) replaced this name with Lasioglossum (Dialictus) hitchensi Gibbs, 2012 to resolve a case of secondary homonymy.

Lasioglossum (Dialictus) nymphaearum (Robertson, 1895): This name is a junior synonym of L. albipenne (see Gibbs et al. 2017a). Lasioglossum (Dialictus) oceanicum (Cockerell, 1916) is the valid name for the species typically referred to as L. nymphaearum.

Lasioglossum (Evylaeus) macoupinense (Robertson, 1895): Although L. macoupinense is retained on the list, it is used for a different species. The earlier use of this name and most applications of it prior to Gibbs et al (2013) refer to Lasioglossum (Hemihalictus) birkmanni (Crawford, 1906).

Lasioglossum (Dialictus) perspicuum (Knerer & Atwood, 1966): Gibbs (2010) synonomized this name with Lasioglossum (Dialictus) admirandum (Sandhouse, 1924).

Lasioglossum (Paralictus) asteris (Mitchell, 1960): Gibbs (2011) synonomized this name with Lasioglossum (Dialictus) lionotus (Sandhouse, 1923).

Megachile (Eutricharaea) concinna Smith, 1879: considered a synonym of Megachile (Eutricharaea) pusilla by Soltani et al. (2017).

Stelis (Microstelis) vernalis Mitchell, 1962: synonymized with Stelis (Stelis) coarctatus Crawford, 1916 by Parker and Griswold, in Gibbs et al. (2017).

When available, the year of determination was used to update the taxonomy of specimen records in the databases we reviewed. Otherwise, specimen data was presented for the species it was recorded as. Notes are included within the checklist for species of Andrena F., Ceratina Latreille, and Lasioglossum that may have records attributable to different species reported under their name. For the purpose of species counts at the state and county levels, and figure data, occurrence records for Augochloropsis metallica sensu lato F., 1793 and A. metallica fulgida Smith, 1853 were combined.

Figures

Figures were created in Microsoft Excel (version 16.16.17), Adobe Illustrator (version 23.1.1), and R 3.4.1 in RStudio (R Core Team 2017; RStudio Team 2015), using the following packages: dunn.test (Dinno 2017), ggmap (Kahle and Wickham 2013) ggplot2 (Wickham 2016), grid (R Core Team 2017), mapdata (Becker et al. 2016), mapproj (McIlroy 2017), maps (Becker et al. 2017), plyr (Wickham 2011), and raster (Hijmans 2017).

Results and discussion

We record 437 species of bees in Pennsylvania by adding 79 new species from our review, removing eight species based on unverifiable records, and accounting for six species removed from the total due to synonymies, compared to those included in the previous state checklist (Donovall and vanEngelsdorp 2010; Fig. 1). We present the first literature reports that we are aware of for 49 species in the state. There are new species records for five of the six North American bee families. Apidae has the most species recorded (118 spp.), followed by Halictidae (110 spp.), Andrenidae (100 spp.), Megachilidae (81 spp.), Colletidae (24 spp.), and Melittidae (4 spp.) (Fig. 1). We newly report the occurrence of three genera in the state (Melecta Latreille, Melitoma Lepeletier and Serville, and Pseudoanthidium Friese), for a total of 46 genera. These measures of biodiversity are comparable to that of neighboring jurisdictions including Connecticut (349 spp.; Zarrillo et al. 2016), Maine (278 spp.; Dibble et al. 2017), Maryland (442 spp.; North American Native Bee Collaborative 2017; Sam Droege, pers. comm.), Michigan (467 spp.; Gibbs et al. 2017a; Jamieson et al. 2019), New York (416 spp.; Danforth and van Dyke 2015 / 447 spp.; Ascher et al. 2014), Ontario (427 spp.; Sheffield et al. 2017; Bees of Canada 2020), and West Virginia (301 spp.; McKinney 2016) (Fig. 2). In addition, we provide a list of nine dubious species records and a list of 11 species that potentially occur in Pennsylvania, with notes about their current known distributions. Our checklist contributes to ongoing projects that document bee biodiversity in North America. In addition to the checklists summarized above, additional checklists now available or in progress include Colorado (Scott et al. 2011), Illinois (Decker et al., in review), Indiana (Jean 2010), Louisiana (Owens et al. 2018), Massachusetts (Goldstein and Ascher 2016), northern Arizona (McCabe et al. 2020), and Wisconsin (Wolf and Ascher 2009; Scott et al. 2011). The bees of the following states are also being surveyed: Montana (Casey Delphia, pers. comm.), New York (New York Natural Heritage Program 2019), Oregon (Andony Melathopoulos, pers. comm.), and Virginia (Ellison Orcutt, pers. comm.).

Figure 1. 

The numbers of bee species by family and per checklist study in Pennsylvania. Blue portions of bars represent the number of species reported in the previous checklist (Donovall and vanEngelsdorp 2010); orange portions of bars denote data from our study. The number inside the blue portion of each bar represents the number of species retained from the previous checklist. Numbers with “-” and enclosed in parentheses indicate taxa removed from the state checklist due either to unverifiable records or synonymy. The numbers with “+”, either inside the orange portion or adjacent to the end of each bar, signify new state species records. The families rank from least to greatest number of species as follows: Melittidae (4 spp.), Colletidae (24 spp.), Megachilidae (81 spp.), Andrenidae (100 spp.), Halictidae (110 spp.), and Apidae (118 spp.).

Sixty-five of 67 counties (all except for Forest and Mifflin) have new species records (Fig. 3; Suppl. material 1). The number of species reports for counties ranges from one (Cameron Co.) to 246 (Adams Co.) (Fig. 3). Even counties that had high species richness reported in the previous checklist had new records. For example, Allegheny, Centre, Cumberland, Dauphin, Delaware, and Philadelphia counties, each had over 100 species listed previously, but all had new records (Donovall and vanEngelsdorp 2010; Fig. 3). Notably, these six counties also have large institutional insect collections located in or near them. Furthermore, Adams and Centre counties have been intensively sampled in the past decade, primarily due to high agroecological and habitat management research activity within their borders, and currently have the highest documented species richness in the state (Fig. 3). However, species expected to be widespread remain undocumented for these seven counties and many parts of the state (Suppl. material 1). Additionally, there are still regions within the state that appear under-surveyed, particularly in the western part of the state (Fig. 3; Suppl. material 1). Sampling of such areas would likely yield additional species records and they should be targeted for future studies to increase information about bee species’ distributions across the state (Jamieson et al. 2019). Counties adjacent to neighboring states also have the potential to record new state records as changes in species’ distributions occur (i.e., Mikulas and Barringer 2018). By updating the first checklist within a decade of its publication, our work has shown that checklists are not static. Regularly compiling species and specimen data, and adding additional analyses, could allow species’ relative abundances to be tracked overtime. Undoubtably, additional specimen material and records will contribute new data for bee species in Pennsylvania in the future.

Figure 2. 

Map of northeastern North America with relative bee species richness. The number of bee species reported for Pennsylvania (this study), and neighboring provinces and states, is shown: Connecticut (Zarrillo et al. 2016), Maine (Dibble et al. 2017), Maryland (North American Native Bee Collaborative 2017; Sam Droege, pers. comm.), Michigan (Gibbs et al. 2017a; Jamieson et al. 2019), New York (Danforth and van Dyke 2015; Ascher et al. 2014), Ontario (Sheffield et al. 2017; Bees of Canada 2020), and West Virginia (McKinney 2016).

Our records also include the presence of at least 23 exotic species. This includes three species not previously reported in Pennsylvania to our knowledge: Coelioxys coturnix Pérez, 1884, Hoplitis anthocopoides (Schenck, 1853), and Pseudoanthidium nanum (Mocsáry, 1881). These species were generally expected to reach the state, based on where they were first confirmed in North America, and in some cases, where they have spread since detection (Sheffield et al. 2011a; Russo 2016; Portman et al. 2019; USGS Native Bee Laboratory 2019). We also add distribution data for Anthophora villosula Smith, 1854, which was reported in Donovall and vanEngelsdorp (2010), but not included on the main checklist. Lasioglossum zonulum (Smith, 1848) is listed as an exotic species, based on recent evidence (Giles and Ascher 2006; USGS Native Bee Laboratory 2019). Additionally, the earliest verified year of collection for Osmia cornifrons (Radoszkowski, 1887) in Pennsylvania is updated to 2002, six years earlier than previously published (Donovall and vanEngelsdorp 2010). Non-native species can potentially out-compete native bees for resources, transmit diseases and parasites, change pollination effectiveness and network structures, and hybridize with local species/populations (Russo 2016; Portman et al. 2019). On the other hand, exotic species may also have positive effects, serving as pollinators of native and agricultural plants, bioindicators and biological control agents, and as study systems for biology and natural history (Russo 2016; Portman et al. 2019). Checklists and monitoring programs that include regular faunistic surveys can be used to readily detect exotic species and identify their effects on local taxa over time.

Figure 3. 

Choropleth map of Pennsylvania specifying bee species richness by county. The greater number of species recorded for a county, the darker blue the county is on the map; lighter-colored counties have fewer species reported from them. The number of species reports for counties ranges from one (Cameron Co.) to 246 (Adams Co.).

Our list includes five species of conservation concern. We include one endangered species, Bombus affinis Cresson, 1863, which has been federally listed since 2017 (U.S. Fish and Wildlife Service 2019; Xerces Society for Invertebrate Conservation 2019b). Other currently threatened or declining bumble bee species that occur in Pennsylvania are B. fervidus (F., 1798), B. pensylvanicus (DeGeer, 1773), and B. terricola Kirby, 1837 (Xerces Society for Invertebrate Conservation 2019b). Epeoloides pilosulus (Cresson, 1878) is also considered a species of conservation concern due to extreme rarity within its range since the 1960s (Bartomeus et al. 2013; Wood et al. 2019; Xerces Society for Invertebrate Conservation 2019a); it has not been recovered in Pennsylvania since 1911 according to our data. The population status for many bee species remains unassessed; other taxa may be experiencing declines or other changes, and require further study. In the absence of these data, we present a breakdown of the number of years since collection for all Pennsylvanian taxa (Fig. 4; Suppl. material 1). The majority of bee species in the state have been collected between 2000–2018, but at least 56 species (12.8% of all species in the state) have not been detected within that time frame (Fig. 4; Suppl. material 1). An additional 15 species with no year of collection available are the result of specimens reported in the literature with either no or limited collecting event information. These species’ collection years, based on the years of publication which they are referenced in, range from pre-1908 to pre-2011. Of the species that Colla et al. (2012) listed as unrecorded in the eastern North America between 1990–2009, one was also undocumented in Pennsylvania between 1990–2018: Andrena mendica Mitchell, 1960, most recently collected in Pennsylvania in 1937 (Suppl. material 1). Contrastingly, two of the unrecorded species listed by Colla et al. (2012) were collected in Pennsylvania within the same time period: A. daeckei Viereck, 1907 and Sphecodes smilacinae Robertson, 1897, last collected in 2007 and 2011, respectively (Suppl. material 1). It is possible that species which have not been recently collected are still present in Pennsylvania but are not represented in the datasets we analyzed. Expeditions specifically focused on collecting these species based on their historical reports would reveal more information about their present status. However, it is also difficult to assess the status of species that have just recently been reported in the state and their populations could also be surveyed to provide these data. We update the most recent year of collection/observation in Pennsylvania for 276 species, compared to data presented in Donovall and vanEngelsdorp (2010). For 105 species, the difference between the most recent year of collection, between the previous checklist and our data, was greater than 20 years (ranging from 23–139 years), further showing the importance of regular and widely-ranging surveys (Donovall and vanEngelsdorp 2010; Suppl. material 1).

Figure 4. 

The number of bee species by their most recent years of collection/observation in Pennsylvania. The number within each bar represents the total number of species in the specified time period. Of the species in the state, 366 (83.8%) have been detected between 2000–2018, while at least 56 species (12.8%) have not. No date of collection/observation was available for 15 species (3.4%).

We contribute floral visitation records with specimen collection data for many species (Suppl. materials 36, 11), and increase phenology information. We note that female bees collected on plants may not have been foraging for pollen or nectar, or at all. Furthermore, some records are attributable to male individuals as well; specimens’ sexes were not always indicated in databases or the literature. Thus, “host plant” status for plant taxa listed must be interpreted with caution. Biological and ecological information for Pennsylvania bee taxa can be found in Hurd (1979), Michener (2007), Fowler (2016), Gibbs et al. (2017), Danforth et al. (2019), as well as the previously-cited reviews and revisions. As approximately 15% of northeastern United States native bee species are specialists (Fowler 2016), focused collections on plant taxa known to attract oligolectic species may contribute additional bee taxa to the Pennsylvanian checklist. Additionally, of the data used in this study, few specimen records were from early- and late-season collections. These gaps can be filled by additional surveying during these time periods throughout the state.

We included information from eight databases, 39 literature sources, three collections, and three additional datasets, and focused on specimens in Pennsylvania which were identified by experts and deposited in collections, without overlapping material addressed in Donovall and vanEngelsdorp (2010). We acknowledge that the datasets compiled for our study were not exhaustive; additional specimen records exist, which are not reflected in our data. Furthermore, our inclusion of AMNH, BugGuide, iNaturalist, and GBIF records in the checklist was limited to a few specimens with reliable determinations. We include all of the BugGuide and iNaturalist reports we retrieved as supplementary data and the GBIF records are accessible online (Suppl. material 1217; GBIF Occurrence Download https://doi.org/10.15468/dl.wghcks). Records from other sources were either not retrieved in our process or not included due to difficulties accessing the data contained, validating identifications, and/or the lack of voucher specimens/images that could be examined in the future (Wheeler et al. 2004; Turney et al. 2015; Funk et al. 2018; Packer et al. 2018). Additional data, along with specimens in other collections, could be incorporated into future checklist updates.

Tracking the fate of specimens used for studies, within collections, loans, or deaccessioned material, using barcodes or a similar system, is critical for retrieving or evaluating vouchers’ statuses. We follow recommendations for generating reproducible and verifiable specimen-based entomological research (Packer et al. 2018) as closely as possible. Our limitations include not knowing what materials were used to identify specimens and the ability to place accession numbers on individual specimens. The specimens in the datasets we used represent vouchers (Yoshimoto 1978). Lists of specimen records used, associated with species name (used in the respective database; not necessarily the most taxonomically-updated name), and specimen code, identifier, and determination date when available, is included to assist with tracking individual materials within their respective collections (Suppl. material 29, 11). Providing this data allows others to more easily locate specimens used as records and verify them, or use them in future studies.

One of the challenges of biodiversity work, which was apparent in our project, was the wide range of formats used to capture specimen data. There was little standardization between the datasets we reviewed as each of them had been created for different purposes. Based on the variety we encountered, we recommend that database columns be clearly labeled and metadata describing the contents of each column should accompany it. This will avoid assumptions about what one header or another means as these may differ between databases. One example of standardized terms for biological data is Darwin Core (https://dwc.tdwg.org/). Additionally, in some cases, readily-available and detailed information about the data contained in the database itself would have been helpful. Examples include knowing if the text in the database was copied verbatim or from the label or if it had been transformed in any way, and if and how specimen localities had been georeferenced. Providing this information will make the data set easier to navigate for use in biodiversity research and other projects. Additionally, it was often unclear who was responsible for identifying individual specimens or when the specimen was identified. This was problematic as there was no credibility directly associated with the specimen record. We were often able to confirm who would have examined the material, though that data had not been entered into the database. A possibility for why the name would have been excluded from the database is that the individual specimen did not have a determination label attached. Therefore, we suggest that determination labels be printed for individual specimens when they are identified, not just the first specimen in a series, so that there is no confusion on who identified the specimen and the credibility of the identification in the future, when it is examined or entered into a database. Determination date should be considered just as important as the determiner field in a database due to changes in taxonomy or nomenclatural usage that can be traced to specific years [e.g., L. birkmanni and L. macoupinense; Gibbs et al. 2013)].

Updating the checklist of bee species known in Pennsylvania provides baseline data for future research on bee biodiversity, ecology, and conservation in the state. By identifying less-surveyed areas, seasons, and species, targeted collecting can be planned to fill gaps in our knowledge. Our results will inform future updates to the Pennsylvania Pollinator Protection Plan (P4), which provides recommendations for supporting pollinator populations (P4 Task Force 2019). Through open access publishing, we also allow these current data to become more readily accessible to all who are interested in understanding bee biodiversity. This also opens the door to future research projects where connections can be made between academia and interested parties; anyone can contribute data on bee biodiversity and potentially discover something entirely new (e.g., Best et al. 2019). Our checklist provides baseline data for more “boots on the ground” by encouraging people to document the species and their natural histories that may be in their own backyards (Wilson 2017).

Checklist

All records for the bee species reported from Pennsylvania that we examined (new and previously reported) are presented here. Within each bee family, taxa are arranged alphabetically first by subfamily, then tribe, genus, subgenus (when applicable), and finally by species name. Each species record consists of the counties for which a voucher specimen or verifiable record has been confirmed. The earliest and latest dates, or only date(s) of collection in Pennsylvania are presented. The most recent year of collection in Pennsylvania is also shown in parentheses. Exotic species are indicated by an asterisk (*) followed by the earliest verified Pennsylvania collection year in parentheses. Bold text indicates a new Pennsylvanian record, previously unpublished to our knowledge and of any type (state, county, date, or most recent year of collection). The source(s) for each record are indicated with superscript numbers defined in the Legend. The source for statewide distribution records with no further data are presented directly after the species name or the earliest verified Pennsylvania collection year, if the species is exotic. AMNH records included in the checklist are presented with their specimen code; full specimen records can be obtained on Discover Life using the ‘Retrieve ID’ function (available at https://www.discoverlife.org/mp/20l?act=enter_id). BugGuide records included in the checklist are shown with their Image IDs; full data is available via links in Suppl. material 1216. Additional BugGuide and all iNaturalist occurrence records for bees in Pennsylvania that are not included below can be found in the Suppl. material 1217. GBIF data is available online at https://doi.org/10.15468/dl.wghcks. Notes are also presented for certain species, particularly those whose older records may apply to other species as a result of recent taxonomic treatments. Lists of species excluded and species expected to occur in Pennsylvania are presented following the checklist.

Legend: 1 = Donovall and vanEngelsdorp (2010); 2 = Bartomeus et al. (2013); 3 = Biddinger Laboratory Database; 4 = Droege Database; 5 = Integrated Crop Pollination (ICP) Project: Fleischer Laboratory Database; 6 = López-Uribe Laboratory Database; 7 = Mahan et al., in prep; 8 = Winfree Laboratory Database; 9 = Choate et al. (2018); 10 = Baker, J.R. (1975); 11 = Bouseman, J.K. and LaBerge, W.E. (1978); 12 = Broemeling, D.K. (1998); 13 = Cockerell, T.D.A. (1908); 14 = Daly, H.V. (1973); 15 = DeBarros, N.B. (2010); 16 = Droege et al. (2010); 17 = Gibbs (2010); 18 = Gibbs (2011); 19 = Gibbs and Dathe (2017); 20 = Gibbs et al. (2013); 21 = LaBerge (1969); 22 = LaBerge (1971); 23 = LaBerge (1973); 24 = LaBerge (1977); 25 = LaBerge (1980); 26 = LaBerge (1985); 27 = LaBerge (1987); 28 = LaBerge (1989); 29 = LaBerge and Bouseman (1970); 30 = LaBerge and Ribble (1972); 31 = Matteson et al. (2008); 32 = McGinley (1986); 33 = McGinley (2003); 34 = Mikulas and Barringer (2018); 35 = Milliron (1973a); 36 = Mitchell (1960); 37 = Mitchell (1962); 38 = Onuferko (2017); 39 = Onuferko (2018); 40 = Ordway (1966); 41 = Rehan and Sheffield (2011); 42 = Roberts (1972); 43 = Shinn (1967); 44 = Sidhu (2013); 45 = Stephen (1954); 46 = Svensson et al. (1977); 47 = Timberlake (1975); 48 = AMNH; 49 = BugGuide; 50 = Swenk (1915); 51 = PSUB; 52 = Rosemary Malfi Insect Collection; 53 = Emily Erickson/BIML.

Melittidae

Melittinae

Macropidini

Genus Macropis Panzer

Taxonomy: Michez and Patiny (2005); Mitchell (1960).

Subgenus Macropis Panzer s. s.

Macropis (Macropis) ciliata Patton, 1880 – Bucks1, Centre7, Cumberland1, Dauphin1, Delaware1, Lancaster1, Lehigh1, Philadelphia2; 12 Jun1 – 9 Jul1 (20177).

Macropis (Macropis) nuda (Provancher, 1882) – Lehigh1, Pike1,2; 21 Apr1 – 9 Jul1 (19831).

Macropis (Macropis) patellata Patton, 1880 – Bucks1, Cumberland1, Dauphin1, Huntingdon1, Lehigh1, Philadelphia1,2; 3 Jun2 – 14 Jul1 (19221).

Melittini

Genus Melitta Kirby

Taxonomy: Michez and Eardley (2007); Mitchell (1960).

Subgenus Cilissa Leach

Melitta (Cilissa) melittoides (Viereck, 1909)36 – Centre1; 16 Jun1 (19581).

Apidae

Apinae

Anthophorini

Genus Anthophora Latreille

Taxonomy: Mitchell (1962); Brooks (1983); Černá et al. (2017).

Subgenus Anthophora Latreille s. s.

Anthophora (Anthophora) villosula Smith, 1854* (20133,8)1Adams3, Union8; 10 Apr328 Apr8 (20133,8).

Subgenus Clisodon Patton

Anthophora (Clisodon) terminalis Cresson, 186937Adams3,8, Allegheny1, Blair1,2, Bradford8, Centre1, Chester1, Cumberland1, Dauphin1, Erie9, Fayette1, Franklin1, Huntingdon1,8, Lycoming8, Montgomery1, Northumberland1, Perry1, Philadelphia1, Susquehanna8, Union8, York1; 14 May323 Oct3 (20183).

Subgenus Lophanthophora Brooks

Anthophora (Lophanthophora) ursina Cresson, 1869 – Schuylkill1,2; 28 May2 – 29 May1 (19881,2).

Subgenus Melea Sandhouse

Revision: Brooks (1983).

Anthophora (Melea) abrupta Say, 1837 (bomboides group)37Adams3, Allegheny1, Cumberland1, Dauphin1, Lackawanna2, Lehigh1, Montgomery1,7, Tioga1; 10 Apr3 – 17 Aug3 (20183).

Anthophora (Melea) bomboides Kirby, 1837 (bomboides group)37Adams3, Allegheny1, Carbon1, Centre1,15, Dauphin6, Huntingdon6, Lehigh1, Montgomery7, Northumberland1, Union8, Washington6; 23 Apr616 Aug3 (20183).

Genus Habropoda Smith

Habropoda laboriosa (Fabricius, 1804) – Adams3, Bucks8, Cumberland1, Dauphin1, Huntingdon8, Lycoming8, Philadelphia1, York8; 21 Mar3 – 4 Jun1 (20153,8).

Apini

Genus Apis Linnaeus

Apis (Apis) mellifera mellifera Linnaeus, 1758* (18871)37Adams3,6, Allegheny6, Beaver44, Bedford6, Berks6, Bradford4,6, Bucks4, Cambria4,6, Carbon6, Centre5,6,7,15,44, Clearfield4,6, Clinton6, Columbia5, Crawford4,6, Cumberland6, Dauphin4,6, Delaware4, Elk6, Erie6,9, Franklin6, Fulton44, Huntingdon3, Jefferson6, Juniata6,44, Lackawanna4, Lancaster3,5,6,15,44, Lebanon4, Lycoming6,44, McKean4, Monroe6, Montgomery6,7,44, Montour6, Northampton5,6, Perry6, Pike4, Schuylkill4, Snyder4, Somerset6, Tioga4, Warren6, Washington6, Westmoreland4,6, York4,6; 14 Mar1 – 17 Nov1 (20173,7). Notes. This non-native species, previously reported has having a ubiquitous distribution in Pennsylvania (Donovall and vanEngelsdorp 2010), undoubtedly occurs in all counties due to its status as a managed pollinator.

Bombini

Genus Bombus Latreille

Taxonomy: Milliron (1971, 1973a, b); Mitchell (1962); Laverty and Harder (1988); Williams et al. (2008, 2014).

Subgenus Bombias Robertson

Bombus (Bombias) auricomus (Robertson, 1903) – Adams3,8, Allegheny1, Bradford1, Bucks1,2, Centre1,44, Cumberland1, Dauphin1, Delaware1,4, Erie1, Fayette1, Huntingdon3, Juniata1, Lancaster3, Lawrence1, Lebanon1, Lehigh1, Montgomery1,8, Northumberland1, Philadelphia1, Somerset1, Tioga1, Washington1, Westmoreland1; 27 Apr1 – 13 Sep1 (20173).

Subgenus Bombus Latreille s. s.

Bombus (Bombus) affinis Cresson, 1863 – Allegheny1, Bucks2, Centre1, Clinton1, Columbia2, Cumberland1, Dauphin1, Delaware2,52, Erie1, Fayette1, Forest1, Fulton1, Huntingdon1, Juniata1, Lackawanna2, Lancaster1, Lawrence1, Lehigh1, Luzerne1,2, Lycoming1, McKean1, Monroe1,2, Northumberland1, Perry1, Philadelphia1,2, Tioga1, Venango1, Warren1, Washington1, Westmoreland1,2, York1; 22 Apr1 – 4 Oct1 (200652).

Bombus (Bombus) terricola Kirby, 1837 – Blair1, Centre1,2,6,15, Clearfield1, Clinton1, Columbia1, Erie1, Huntingdon1, Lackawanna2, Luzerne1,2, Lycoming1, McKean1, Monroe1,2, Pike1, Sullivan1, Tioga1, Warren1; 29 Apr2 – 2 Nov1 (200915).

Subgenus Cullumanobombus Vogt

Bombus (Cullumanobombus) griseocollis (DeGeer, 1773) (griseocollis group) – Adams3,6,8, Allegheny1,35, Berks2, Bradford1, Bucks1,2,6,8, Centre1,6,7,15, Chester1,8,44, Columbia5, Cumberland1, Dauphin1,4,6, Delaware1,2,4, Erie1, Fayette1,35, Huntingdon1,8, Lancaster1,3,4,5,6,15,44, Lebanon4, Lehigh1, Luzerne2, Lycoming6, Monroe1,2, Montgomery7,8, Perry1,4, Philadelphia1,4, Pike1, Snyder4, Tioga1, Union8, Washington1, Westmoreland1,35, York4,6,8; 10 Apr312 Oct3 (20183).

Bombus (Cullumanobombus) rufocinctus Cresson, 1863 (rufocinctus group) – Erie34; 30 Jul34 (201734).

Subgenus Psithyrus Lepeletier

Bombus (Psithyrus) ashtoni (Cresson, 1864) (bohemicus group) – Allegheny1, Berks2, Centre1,2,15, Columbia2, Cumberland1, Dauphin1, Erie1, Lackawanna1, Perry1, Westmoreland1; 12 May1 – 26 Sep2 (200915).

Bombus (Psithyrus) citrinus (Smith, 1854) (citrinus group) – Allegheny1, Berks1, Bucks8, Centre1,15, Columbia1, Cumberland1, Dauphin1, Erie1, Fulton1, Huntingdon1, Lancaster1,3, Lehigh1, Lycoming1, Monroe2, Northumberland1, Perry1, Philadelphia4, Pike1, Westmoreland1, York1; 2 Apr1 – 14 Nov1 (20123).

Bombus (Psithyrus) fernaldae (Franklin, 1911) (sylvestris group) – Adams1,3, Centre1,6,7,15, Erie9; 6 May615–16 Aug7 (20167).

Bombus (Psithyrus) insularis (Smith, 1861) (citrinus group) – Centre1,15, Cumberland1, Perry1; 23 Jun1 (200915).

Subgenus Pyrobombus Dalla Torre

Bombus (Pyrobombus) bimaculatus Cresson, 1863 (lapponicus group) – Adams1,3,8, Allegheny1, Beaver44, Bedford1,6, Blair6, Bradford6,8, Bucks6,8, Centre1,3,5,6,7,15,44, Chester8, Columbia5, Crawford1, Cumberland1, Dauphin1,6, Delaware1,2,4, Erie9, Fulton1, Huntingdon1,2,3,8, Jefferson6, Juniata1, Lackawanna1,2, Lancaster1,3,5,8, Lebanon1, Lehigh1,6, Lycoming6,8, Mifflin1, Monroe1, Montgomery7,8, Northampton5,6, Northumberland1, Perry1, Philadelphia1,2, Pike1,4, Schuylkill2,4, Somerset1,6, Susquehanna8, Union1,8, Washington1, Westmoreland1, York1,8; 14 Mar1 – 12 Nov1 (20183).

Bombus (Pyrobombus) impatiens Cresson, 1863 (lapponicus group)37 – Adams3,8,44, Allegheny1, Beaver44, Bedford6, Berks6, Blair6, Bradford1,4,6,8, Bucks1,4,6,8, Butler1,44, Cambria6, Carbon1,6, Centre1,5,6,7,8,15,44, Chester1,6,8,44, Clearfield1,4, Clinton1,6, Columbia2,5, Crawford1,6, Cumberland1, Dauphin1,4,6, Delaware1,2,4,6,44, Erie1,6,9, Fayette1, Franklin1, Fulton1,3,44, Huntingdon1,3,8, Indiana1, Jefferson1,6, Juniata1,3,6,44, Lackawanna1,2,4,6, Lancaster1,2,3,4,5,6,8,15,44, Lebanon1,4,6, Lehigh1,6, Luzerne1,2, Lycoming1,6,8,44, McKean1,4, Mifflin1, Monroe1,2,6, Montgomery1,2,6,7,8,44, Northampton5,6, Northumberland1,6, Perry1,4, Philadelphia1,2,4,6, Schuylkill4,6, Snyder4, Somerset6, Sullivan1, Susquehanna8, Union1,8, Washington1, Wayne1, Westmoreland1,6, Wyoming4, York1,4,6,8,44; 31 Mar3 – 12 Nov1 (20183).

Bombus (Pyrobombus) perplexus Cresson, 1863 (hypnorum group) – Adams1,3,8, Beaver44, Bradford4,6,8, Bucks2,8, Centre1,3,6,7,15,44, Columbia2,5, Dauphin6, Delaware2, Erie9, Huntingdon3,8, Juniata3, Lackawanna2,4, Lancaster1,3,4,6, Lebanon6, Lycoming8, McKean4, Monroe4, Montgomery7, Northampton4, Philadelphia2, Schuylkill2, Union8, York6,8; 12 Apr3 – 27 Dec1 (20183).

Bombus (Pyrobombus) sandersoni Franklin, 1913 (pratorum group)37Adams3, Allegheny1, Bucks1, Carbon1, Centre1,3,6,7, Chester1, Cumberland1, Dauphin1, Delaware1, Franklin1, Huntingdon1, Lackawanna2, Lebanon6, Lehigh1, McKean1, Monroe1, Northumberland1, Perry1, Philadelphia1, Schuylkill2, Sullivan1, Tioga1, Union8, Westmoreland1; 29 Apr215–16 Aug7 (20177).

Bombus (Pyrobombus) ternarius Say, 1837 (lapponicus group)37 – Bradford1,4,6,8, Carbon1,6, Centre1,44, Clinton1, Columbia1,5, Crawford1, Huntingdon1, Lackawanna1,2, Lancaster3,44, Luzerne1,2, Lycoming1, McKean1, Monroe1,2, Perry1, Schuylkill6, Sullivan1, Wayne2; 25 Apr1 – 16 Oct1 (20155).

Bombus (Pyrobombus) vagans vagans Smith, 1854 (vagans group)37 – Adams1,3,8, Allegheny1, Beaver1,44, Bedford1, Berks2, Blair2, Bradford4,8, Bucks1,8, Butler1, Cambria1, Centre1,3,7,15,44, Chester1,8, Clearfield4, Clinton1, Columbia1,2,5, Crawford1,4,6, Cumberland1, Dauphin1, Delaware1,2, Erie1,9, Fayette1, Forest1, Franklin1, Fulton1, Huntingdon1,2,8, Juniata1,44, Lackawanna2,4, Lancaster1,3, Lebanon1, Lehigh1, Luzerne1, Lycoming1,8,44, McKean1,4, Monroe2, Montgomery1,8, Northumberland1, Perry1, Philadelphia1, Pike1,2,4, Schuylkill1,2,4, Somerset6, Sullivan1, Susquehanna8, Tioga1,6, Union1,8, Warren1,6, Washington1, Westmoreland1, Wyoming1, York1,4,8; 31 Mar3 – 3 Nov1 (20183).

Subgenus Subterraneobombus Vogt

Bombus (Subterraneobombus) borealis Kirby, 1837 – Adams3, Allegheny1, Beaver1, Tioga1; 11 Aug124 Sep3 (20153).

Subgenus Thoracobombus Dalla Torre

Bombus (Thoracobombus) fervidus (Fabricius, 1798) (pensylvanicus group)37 – Adams1,3,8, Allegheny1, Berks1,2, Bradford8, Bucks1,8, Centre1,7,44, Chester1,8, Clinton1, Columbia1,2,5, Crawford4, Cumberland1, Dauphin1,6, Delaware1,4,6, Erie1, Forest1, Franklin1, Greene1, Huntingdon1,2, Lackawanna2, Lancaster1,3,5,8,15, Lawrence1, Lehigh1, Luzerne1, Lycoming8, Mifflin1, Montgomery1,2,8, Northampton5, Northumberland1, Philadelphia1,2,4, Tioga1, Washington1, Westmoreland1, York1,8; 31 Mar3 – 4 Nov1 (20183).

Bombus (Thoracobombus) pensylvanicus (DeGeer, 1773) (pensylvanicus group)37Adams3, Allegheny1, Beaver1, Berks2, Centre1,44, Chester1, Clarion1, Columbia1,2,5, Crawford1, Cumberland1, Dauphin1, Delaware1,4, Erie1, Fayette1, Jefferson1, Juniata1, Lancaster1, Lebanon1, Mifflin1, Monroe2, Montgomery1, Philadelphia1,2, Tioga1, Union1, Washington1, Westmoreland1, York1; 23 Apr1 – 15 Oct1 (20183).

Emphorini

Genus Melitoma Lepeletier and Serville

Taxonomy: Mitchell (1962).

Melitoma taurea (Say, 1837) – Adams3, Lancaster3,8; 12 Jun3– 2 Oct3 (20183).

Genus Ptilothrix Smith

Taxonomy: Mitchell (1962).

Ptilothrix bombiformis (Cresson, 1878) – Adams3,8, Delaware1,4, Montgomery8, York8; 26 Apr3 – 2 Oct3 (20183).

Eucerinae

Eucerini

Genus Eucera Scopoli

Taxonomy: Dorchin et al. (2018).

Subgenus Cemolobus Robertson

Taxonomy: Mitchell (1962). Monotypic.

Eucera (Cemolobus) ipomoeae (Robertson, 1891) – Adams3; 5 Jul3 – 30 Jul3 (20173).

Subgenus Peponapis Robertson

Revision: Hurd and Linsley (1964).

Key: Ayala and Griswold (2012).

Eucera (Peponapis) pruinosa (Say, 1837)37Adams3,8, Allegheny1, Armstrong6, Beaver44, Berks6, Bradford6,8, Bucks8, Centre1,5,6,7,15,44, Chester8, Columbia5, Crawford4, Cumberland6, Dauphin1,6, Delaware4, Erie1,9, Franklin6, Fulton44, Huntingdon3,8, Jefferson6, Juniata44, Lancaster3,5,6,8,15,44, Lebanon6, Lycoming8,44, Monroe6, Montgomery6,8,44, Perry6, Philadelphia1, Union8, Wayne1, Westmoreland1, York1,6,8; 5 May112 Oct3 (20183).

Subgenus Synhalonia Patton

Revision: Timberlake (1969).

Eucera (Synhalonia) atriventris (Smith, 1854)37Adams3, Allegheny1, Centre1, Cumberland1, Dauphin1, Delaware1, Franklin1, Huntingdon3,8, Montgomery1, Philadelphia1, York1; 12 Apr129 Jul3 (20173).

Eucera (Synhalonia) dubitata (Cresson, 1878)37Adams3, Lycoming8; 27 Apr3 – 24 Sep3 (20173).

Eucera (Synhalonia) hamata (Bradley, 1942) – Adams3,8, Delaware4, Huntingdon8, Lancaster3,5,8, York8; 31 Mar3 – 17 Aug3 (20183).

Eucera (Synhalonia) rosae (Robertson, 1900) – Adams3; 17 Apr3 – 5 Jul3 (20173).

Genus Melissodes Latreille

Taxonomy: LaBerge (1955, 1956a, b, 1961); Mitchell (1962).

Subgenus Apomelissodes LaBerge

Revision: LaBerge (1956b).

Melissodes (Apomelissodes) apicatus Lovell & Cockerell, 1906 – Montgomery7; 26 – 27 Jun7 (20177).

Melissodes (Apomelissodes) fimbriatus Cresson, 1878 – Adams3,51; 21 Jun3 – 28 Jun–5 Jul51 (20123,51).

Subgenus Eumelissodes LaBerge

Revision: LaBerge (1961).

Melissodes (Eumelissodes) agilis Cresson, 187837 – Allegheny1, Centre15,44, Dauphin1, Lancaster1,8, Lebanon1, Philadelphia1; 14 Jul1 – 12 Aug1 (20158).

Melissodes (Eumelissodes) boltoniae Robertson, 190537 – Centre1, Forest1; 25 Jun1 – 27 Aug1 (19561).

Melissodes (Eumelissodes) denticulatus Smith, 185437Adams3, Allegheny1, Armstrong1, Beaver1, Centre15,44, Cumberland1, Dauphin1, Elk6, Erie9, Lancaster3, Perry1,4, Philadelphia1, Washington1, York1; 26 May3 – 8 Oct1 (20183).

Melissodes (Eumelissodes) dentiventris Smith, 185437Adams3, Allegheny1, Carbon6, Cumberland1, Dauphin1, Philadelphia1, York1; 3 Jul3 – 17 Oct1 (20153).

Melissodes (Eumelissodes) druriellus (Kirby, 1802)37Adams3, Allegheny1, Bradford8, Centre1,7,15,44, Columbia2, Crawford4, Dauphin1,6, Delaware1, Huntingdon6, Lackawanna1, Lycoming8, Monroe1,2, Montgomery1, Philadelphia1, Tioga1, Union8, Westmoreland1; 11 Jun6 – 29 Sep2 (20177).

Melissodes (Eumelissodes) fumosus LaBerge, 1961 – Centre44; dates not reported44 (2010 – 201244).

Melissodes (Eumelissodes) illatus Lovell & Cockerell, 190637Adams3, Centre15, Erie9; 11 Jun3 – 17 Aug3 (20169).

Melissodes (Eumelissodes) niveus Robertson, 1895 – Center44, Delaware1; 3 Sep1 (2010 – 201244).

Melissodes (Eumelissodes) subillatus LaBerge, 196137Adams3, Huntingdon2, Lancaster3; 14 Jun3 – 6 Sep3 (20143).

Melissodes (Eumelissodes) trinodis Robertson, 190137Adams3, Allegheny1, Bucks8, Centre7, Chester8, Cumberland1, Dauphin1,6, Delaware1,4, Lancaster3,5, Lycoming8, Montgomery8, Philadelphia1, York8; 4 Jun3 – 13 Oct3 (20183).

Subgenus Heliomelissodes LaBerge

Revision: LaBerge (1956b).

Melissodes (Heliomelissodes) desponsus Smith, 185437 – Adams1,3, Bradford4,8, Centre1,2,15,44, Columbia5, Cumberland1, Dauphin6, Delaware4, Erie9, Forest1, Franklin6, Huntingdon3,8, Lancaster3,8, Lebanon1,4, Lycoming8, Philadelphia1, Snyder4, Somerset6, Washington6, York6,8; 23 Apr21 Oct3 (20183).

Subgenus Melissodes Latreille s. s.

Revision: LaBerge (1956a).

Melissodes (Melissodes) bimaculatus bimaculatus (Lepeletier, 1825)37 – Adams1,3,8, Allegheny1, Bedford6, Bradford8, Bucks1,8, Carbon6, Centre1,15,44, Chester1,8, Columbia2,5, Cumberland1, Dauphin1,6, Delaware1,4, Erie9, Franklin1, Fulton44, Huntingdon1,3,8, Juniata1,3, Lancaster1,3,4,5,6,8,15, Lebanon1, Lycoming8,44, Mifflin1, Montgomery1,8,44, Montour1, Perry1,4, Philadelphia1,4, Union8, Washington1, York1,6,8; 26 Apr3 – 31 Oct1 (20183).

Melissodes (Melissodes) communis communis Cresson, 1878 – Allegheny1; dates and year not reported1.

Melissodes (Melissodes) tepaneca Cresson, 1878 – Adams3; 13 Aug3 (20153).

Genus Svastra Holmberg

Subgenus Anthedonia Michener

Revision: LaBerge (1955).

Svastra (Anthedonia) compta (Cresson, 1878) – Philadelphia1; dates and year not reported1.

Subgenus Epimelissodes Ashmead

Revision: LaBerge (1956a).

Svastra (Epimelissodes) obliqua (Say, 1837) caliginosa (Cresson, 1878) – Adams3, Delaware4, Lancaster3; 30 Jun3 – 9 Sep4 (20183).

Nomadinae

Ammobatoidini

Genus Holcopasites Ashmead

Taxonomy: Mitchell (1962); Hurd and Linsley (1972).

Holcopasites calliopsidis calliopsidis (Linsley, 1943) – Adams3,8, Centre1,6,7, Dauphin1, Delaware2, Indiana1, Lackawanna1, Lancaster3,15, Lehigh6, Philadelphia1, Westmoreland6, York1,6; 24–25 May7 – 18 Aug3 (20173).

Holcopasites illinoiensis (Robertson, 1891) – Bucks1; 28 Jun1 (19361).

Epeolini

Genus Epeolus Latreille

Taxonomy: Mitchell (1962); Brumley (1965); Onuferko (2017, 2018).

Epeolus americanus (Cresson, 1878)37 – Dauphin1,37; 6 Jun1 - 27 Jun37 (192337).

Epeolus autumnalis Robertson, 1902 – Centre1, Huntingdon1, Philadelphia2; 27 Apr2 – 20 Sep1 (20031).

Epeolus bifasciatus Cresson, 186437,39Adams3, Berks2, Centre1,15,38,44, Dauphin1, Huntingdon1, Lancaster3,15, Lehigh1, Luzerne2, Philadelphia1; 2 Jul3 – 5 Sep1 (201638).

Epeolus lectoides Robertson, 1901 – Adams6, Philadelphia1; 14 Aug6 – 17 Sep1 (20086).

Epeolus pusillus Cresson, 1864 – Columbia1,2, Lycoming8, Union8; 25 Sep228 Sep8 (20148).

Epeolus scutellaris Say, 182437 – Bradford39, Centre1,7, Erie1, Huntingdon1, Monroe1,2, Philadelphia2; 9 Aug2 – 25 Sep1/Aug–Oct39 (20177).

Genus Triepeolus Robertson

Revision: Rightmyer (2008).

Triepeolus atripes Mitchell, 1962 – Lancaster37; 5 Sep37 (195437).

Triepeolus concavus (Cresson, 1878) – Adams3, Lancaster3; 12 Jul3 - 26 Jul3 (20123).

Triepeolus donatus (Smith, 1854)37Centre7, Forest1, Westmoreland6; 25 May124–25 Jul7 (20177).

Triepeolus helianthi (Robertson, 1897) – Beaver1, Centre1,15, Franklin1; 9 Jul1 – 19 Aug1 (200915).

Triepeolus lunatus (Say, 1824)37 – Adams1,3, Allegheny1, Bucks8, Cumberland1, Dauphin1, Delaware1, Lancaster1,3,6, Montgomery1,8, Perry4, Somerset1, York1; 25 Jun3 – 11 Sep1 (20183).

Triepeolus nevadensis (Cresson, 1878) – Adams3; 4 Aug3 (20163).

Triepeolus pectoralis (Robertson, 1897) – Columbia2, Delaware1,2, York1; 4 Sep1,2 – 29 Sep2 (19922).

Triepeolus quadrifasciatus (Say, 1823) atlanticus Mitchell, 1962 – Huntingdon1; 10 Sep1 (19961).

Triepeolus remigatus (Fabricius, 1804)37Adams3, Bucks8, Centre1,6,44, Chester8, Columbia5, Dauphin1, Delaware1,2,4, Huntingdon1, Juniata44, Lancaster1,3,4,5,15, Lycoming44, Montgomery8,44, Philadelphia1, York8; 9 Jul8 – 7 Sep1 (20145).

Triepeolus rhododontus Cockerell, 1921 – Huntingdon1; 26 Aug1 (19961).

Triepeolus rugosus Mitchell, 1962 – Huntingdon1; 26 Aug1 (19961).

Triepeolus simplex Robertson, 1903 – Union8, York1; 6 Aug124 Aug8 (20158).

Melectini

Genus Melecta Latreille

Subgenus Melecta Latreille s. s.

Revisions: Linsley (1939); Hurd and Linsley (1951).

Melecta (Melecta) pacifica Cresson, 1878 – Adams3; 13 Apr3 (20173).

Nomadini

Genus Nomada Scopoli

Taxonomy: Alexander and Schwarz (1994); Broemeling and Moalif (1988); Droege et al. (2010); Evans (1972); Mitchell (1962); Schwarz and Gusenleitner (2004). Nomada is in serious need of revision (Gibbs et al. 2017a). This list of species is likely to change considerably following the publication of updated taxonomy for the genus.

Nomada affabilis Cresson, 1878 (edwardsii group) – Adams3; 7 Jun3 – 12 Jun3 (20133).

Nomada armatella Cockerell, 1903 (ruficornis group) – Cumberland6, Elk1; 9 Apr116 Apr6 (20086).

Nomada articulata Smith, 1854 (erigeronis group)37Adams3, Bucks8, Cumberland1, Dauphin1, Delaware1, Erie1,9, Huntingdon1,2,8, Luzerne1, Lycoming8, Montgomery1, Philadelphia1, Union1; 25 Apr1 – 8 Jul1 (20183).

Nomada australis Mitchell, 1962 (erigeronis group) – Adams3; 24 May3 – 3 Jun3 (20163).

Nomada bella Cresson, 1863 (ruficornis group: bidentate mandible) – Centre1,2, Cumberland1, Elk1, Huntingdon1, Philadelphia1,2; 27 Mar1 – 12 Jun1 (20092).

Nomada bethunei Cockerell, 1903 (ruficornis group) – Centre1, Cumberland1,6, Huntingdon3, Jefferson6, Northumberland16, Perry1,16, Washington6; 16 Apr6 – 29 Aug1 (20086).

Nomada ceanothi Cockerell, 1907 (ruficornis group) – Columbia5, Cumberland1, Delaware1, Huntingdon3, Montgomery1, York1; 19 Apr1 – 25 Jun1 (20135).

Nomada composita Mitchell, 1962 (ruficornis group) – Adams3, Centre1, Huntingdon8, Lycoming8, Perry6, Susquehanna8, Union8, York8; 2 Apr130 May3 (20158).

Nomada cressonii Robertson, 1893 (ruficornis group)37 – Adams1,3, Blair1,2, Bradford6,8, Bucks8, Centre1,7, Crawford1, Cumberland1, Dauphin1, Delaware1, Elk1, Erie1,9, Huntingdon1,8, Lancaster8, Lehigh1, Lycoming8, Montgomery1, Perry1,6, Philadelphia1, Somerset1, Susquehanna8, Tioga1, Union8, York1,8; 4 Apr6 – 20 Aug1 (20163,7,9).

Nomada cuneata (Robertson, 1903) (ruficornis group: bidentate mandible)37 – Adams2, Blair1,2, Centre1, Dauphin1, Erie1, Franklin1, Huntingdon1, Perry1, Pike1,4, Sullivan1, York1; 3 Apr1 – 26 Jun1 (20061,2).

Nomada denticulata Robertson, 1902 (ruficornis group)37Bradford8, Bucks8, Centre7,8, Columbia5, Cumberland1, Dauphin1, Delaware1, Elk1, Erie9, Franklin1, Huntingdon3,8, Pike1, York1,8; 15 Apr8 – 15 Jun8 (20177).

Nomada depressa Cresson, 1863 (ruficornis group) – Adams3, Bradford8, Bucks8, Centre1, Crawford6, Cumberland6, Dauphin1,6, Huntingdon1,8, Lancaster8, Luzerne1, Lycoming8, Perry6, Susquehanna8, Union8, Warren6; 4 Apr6 – 19 Sep1 (20163).

Nomada fervida Smith, 1854 (vegana group) – Adams3, Erie1; 3 Jun3 – 30 Jul1 (20083).

Nomada fragariae Mitchell, 1962 (ruficornis group) – Centre1, Mercer6; 5 May1 (20096).

Nomada gracilis Cresson, 1863 (ruficornis group) – Dauphin6, Huntingdon1, Susquehanna8, Union8; 11 Apr6 – 28 May1 (20148).

Nomada illinoensis Robertson, 1900 (ruficornis group) – Adams3, Dauphin1; 26 Apr3 – 1 Jul3 (20183).

Nomada imbricata Smith, 1854 (ruficornis group)37Adams3, Bradford8, Centre1,7,8, Crawford1, Cumberland1, Dauphin1, Delaware1,2, Erie9, Huntingdon1,2,8, Lancaster8, Mercer6, Montour6, Philadelphia1,2,4, Susquehanna8, Union8, York1,8; 14 Apr3 – 15 Jun8 (20183).

Nomada integerrima Dalla Torre, 1896 (ruficornis group)37Somerset6, Washington6; 28 May6 – 13 Jun6 (20096).

Nomada lehighensis Cockerell, 1903 (ruficornis group)37 – Adams16, Carbon16, Dauphin16, Erie1,16, Huntingdon8, Lehigh1,16, Lycoming8, Northampton16, Schuylkill2; 1 Apr16 – 21 Jul1 (20158).

Nomada lepida Cresson, 1863 (ruficornis group: bidentate mandible)37Adams3, Columbia5, Cumberland1, Dauphin1, Delaware1, Erie1, Huntingdon3, Philadelphia1; 10 Apr3 – 30 Jun1 (20163).

Nomada luteola Olivier, 1812 (ruficornis group) – Adams3, Dauphin1, Delaware1, Huntingdon1, Montgomery1, Philadelphia1,2, York8; 23 Apr3 – 21 Jun1 (20163).

Nomada luteoloides Robertson, 1895 (ruficornis group) – Adams3,8, Bradford8, Bucks8, Centre1,7,8, Cumberland1, Dauphin1,6, Delaware1, Erie1, Franklin1, Huntingdon1,3,8, Lancaster8, Luzerne1, Lycoming8, Perry6, Philadelphia1, Schuylkill1,2, Susquehanna8, Union8, York1,8; 31 Mar3 – 11 Jun1,8 (20177).

Nomada maculata Cresson, 1863 (ruficornis group: bidentate mandible) – Adams3, Bradford8, Bucks8, Centre1,7, Chester1, Columbia5, Dauphin1, Delaware1, Erie1,9, Huntingdon1,2,8, Lancaster8, Lycoming8, Montgomery1, Perry1, Philadelphia1,2, Pike1,4, Schuylkill1,2, Susquehanna8, Tioga1, Union8, York1,8; 13 Apr1 – 17 Jun1 (20177).

Nomada obliterata Cresson, 1863 (ruficornis group) – Cumberland1, Dauphin1, York1; 30 Apr1 – 27 Jun1 (19701).

Nomada ovata (Robertson, 1903) (ruficornis group: bidentate mandible)37Adams3, Centre1, Cumberland1, Huntingdon1; 16 Apr3 – 11 Jul1 (20133).

Nomada parva Robertson, 1900 (ruficornis group)37Chester6, Dauphin1; 6 May113 Jul6 (20086).

Nomada perplexa Cresson, 1863 (ruficornis group: bidentate mandible)37 – Centre1, Crawford1, Dauphin1, Erie1, Huntingdon1, Lancaster3, Lehigh1, Monroe2, Philadelphia2; 5 Mar1 – 14 Jul1 (20133).

Nomada placida Cresson, 1863 (roberjeotiana group) – Cumberland1,12, Delaware1,2; 28 Aug1,12 – 25 Sep2 (19471).

Nomada pygmaea Cresson, 1863 (ruficornis group)37Adams3, Bradford8, Bucks2,8, Centre7, Columbia5, Cumberland1, Dauphin1, Delaware1, Erie9, Huntingdon2,8, Lancaster8, Lehigh1, Lycoming8, Mercer6, Montgomery1, Philadelphia1, Pike1,4, Susquehanna8, Union8, York1,8; 15 Apr8 – 29–30 Jun7 (20177).

Nomada rubicunda Olivier, 1812 (erigeronis group) – Philadelphia1; dates and year not reported1.

Nomada sayi Robertson, 1893 (ruficornis group)37Adams3, Chester6, Crawford1, Dauphin1,6, Franklin1, Huntingdon1, Montgomery1, Philadelphia1; 17 Apr6 – 11 Jul1 (20163).

Nomada skinneri Cockerell, 1908 (ruficornis group)37 – Carbon13, Lehigh13, Northampton13; 30 Jun13 (year not reported13).

Nomada sulphurata Smith, 1854 (ruficornis group) – Adams3, Dauphin1, Montgomery1; 28 Apr126 May3 (20163).

Nomada superba Cresson, 1863 (superba group) – Adams3; 5 May3 – 12 May3 (20163).

Nomada tiftonensis Cockerell, 1903 (vegana group) – Philadelphia2; 5 May2 (19052).

Nomada ulsterensis Mitchell, 1962 (ruficornis group)37 – Philadelphia50; 18 Jun50 (190550).

Nomada valida Smith, 1854 (ruficornis group) – Adams3, Clinton1, Crawford1; 3 Apr1 – 28 May1 (20153).

Nomada vicina Cresson, 1863 (ruficornis group) – Centre1,7, Erie1, Huntingdon1; 12 Aug1 – 20 Sep1 (20177).

Nomada xanthura Cockerell, 1908 (ruficornis group) – Centre1,7, Pike1; 1 May131 May–1 Jun7 (20177).

Osirini

Genus Epeoloides Giraud

Taxonomy: Mitchell (1962).

Epeoloides pilosulus (Cresson, 1878) – Dauphin1, Lehigh1; 9 Jun1 – 30 Jun1 (19111).

Xylocopinae

Ceratinini

Genus Ceratina Latreille

Subgenus Zadontomerus Ashmead

Taxonomy: Mitchell (1962); Daly (1973); Rehan and Richards (2008); Rehan and Sheffield (2011).

Ceratina (Zadontomerus) calcarata Robertson, 190014,37 – Adams1,3,6,8, Allegheny1,6, Armstrong6, Berks1,6, Bradford1,4,6,8, Bucks1,6,8, Carbon6, Centre1,6,7,8,15,44, Chester1,6, Clarion6, Clearfield1,4, Clinton1, Columbia5, Crawford1, Cumberland1,6, Dauphin1,6, Delaware1,4, Erie1,6,9, Forest1, Franklin6, Greene6, Huntingdon2,3,8, Indiana6, Jefferson6, Juniata1,6, Lackawanna4, Lancaster3,5,6,8,15,44, Lehigh1,6, Lycoming8, Monroe1, Montgomery4,6, Northampton1,6, Northumberland1, Perry1,4,6, Philadelphia1,4, Schuylkill6, Somerset1, Susquehanna8, Union8, Washington1, Westmoreland1, York1,6,8; 23 Mar3 – 6 Nov3 (20183). Notes. Older records for C. calcarata, especially pre-2011 determinations, may be attributable to C. mikmaqi (see Rehan and Sheffield 2011).

Ceratina (Zadontomerus) dupla Say, 183714,37 – Adams1,3,6,8, Allegheny1, Berks1,6, Bradford1,6,8, Bucks1,6,8, Carbon1, Centre1,6,7,8,15,44, Chester1,6, Clearfield6, Clinton6, Columbia5, Crawford1,6, Cumberland1,6, Dauphin1,6, Delaware1,4, Erie1,6,9, Franklin1,6, Huntingdon1,3,8, Jefferson6, Juniata3,6, Lackawanna1,4, Lancaster3,5,6,15, Lawrence1, Lehigh1,6, Lycoming6,8, Montgomery1,4,6,7,44, Northumberland1, Perry1,6, Philadelphia1,6, Pike1, Schuylkill6, Tioga1, Union8, Warren6, Washington6, York1,6,8; 20 Feb1 – 22 Dec1 (20183).

Ceratina (Zadontomerus) floridana Mitchell, 1962 – Delaware4; 21 May4 (20074).

Ceratina (Zadontomerus) mikmaqi Rehan & Sheffield, 201141Adams3,8, Bradford8, Bucks8, Centre7,8, Dauphin48 (AMNH_BEE00172273), Erie9, Huntingdon8, Lancaster3,5,8, Lycoming8, Montgomery7, Union8, York8; 29 Mar3 – 6 Nov3 (20183).Notes. Older records for female C. calcarata and male C. dupla, especially pre-2011 determinations, may be attributable to C. mikmaqi (see Rehan and Sheffield 2011).

Ceratina (Zadontomerus) strenua Smith, 1879 – Adams1,3,6,8, Allegheny1, Armstrong6, Berks2,6, Bradford6,8, Bucks1,2,8, Centre6,7,8,15, Chester1,6,8, Clarion6, Crawford1, Cumberland1,6, Dauphin1,6, Delaware1,4, Erie6,9, Franklin1,6, Huntingdon1,2,3,8, Juniata1,6, Lancaster1,3,6,8,15, Lehigh6, Lycoming8, Monroe4, Montgomery4,6,7,8, Northampton6, Northumberland1,14, Perry1,4,6, Philadelphia1,4, Pike1,4, Union8, Washington6, Westmoreland1, York1,6,8; 31 Mar3 – 4 Dec6 (20183).

Xylocopini

Genus Xylocopa Latreille

Subgenus Xylocopoides Michener

Taxonomy: Hurd (1961); Mitchell (1962).

Xylocopa (Xylocopoides) virginica virginica (Linnaeus, 1771) – Adams1,3,8, Allegheny1,2, Blair1, Bradford6, Bucks1,6,8, Butler1, Centre1,3,5,6,7,15,44, Chester1,8, Clearfield1, Columbia1,2,5, Crawford1, Dauphin1,6, Delaware1, Erie1,9, Fayette1, Forest1, Greene1, Huntingdon1,3,8, Indiana1, Jefferson1, Juniata1, Lackawanna2, Lancaster1,2,3,5,15, Lebanon4, Lehigh1, Luzerne1, Lycoming8, Montgomery1,7,8, Perry1,4, Philadelphia1,2,4, Schuylkill1,2, Snyder4, Union1,8, Washington1, Westmoreland1,2, York1,8; 5 Mar130 Oct3 (20183).

Megachilidae

Megachilinae

Anthidiini

Genus Anthidiellum Cockerell

Subgenus Loyolanthidium Urban

Taxonomy: Mitchell (1962); Urban (2001).

Anthidiellum (Loyolanthidium) notatum notatum (Latreille, 1809) – Centre1, Huntingdon1,2, Lancaster3, Mifflin1, Monroe1, Northampton6, Philadelphia1; 12 Jul1,222 Aug3 (20123).

Genus Anthidium Fabricius

Revision: Gonzalez and Griswold (2013).

Subgenus Anthidium Fabricius s. s.

Anthidium (Anthidium) manicatum manicatum (Linnaeus, 1758)* (19901,6) – Adams3,8, Bradford8, Centre1,2,6,15,44, Cumberland1,6, Dauphin1,6, Delaware4, Erie6,9, Huntingdon1,3, Lancaster8, Lehigh3,6, Lycoming8, Montgomery44, Philadelphia1, Schuylkill6, Sullivan1, Union8, Washington6, York1,8; 25 Mar6 – 19 Oct3 (20183).

Subgenus Proanthidium Friese

Anthidium (Proanthidium) oblongatum oblongatum (Illiger, 1806)* (19941) – Adams3,6, Bradford8, Bucks4,8, Centre1, Columbia1, Crawford1, Cumberland6, Dauphin1,6, Delaware1,4, Erie9, Lackawanna4, Lancaster1,8, Lehigh1,6, Lycoming8, Northampton6, Philadelphia1,4, Union8, Westmoreland4, York8; 14 May3 – 17 Oct1 (20183).

Genus Paranthidium Cockerell and Cockerell

Taxonomy: Schwarz (1926).

Subgenus Paranthidium Cockerell and Cockerell s. s.

Paranthidium (Paranthidium) jugatorium jugatorium (Say, 1824) – Bedford1, Centre1; 28 Jul1 – 29 Aug1 (20061).

Genus Pseudoanthidium Friese

Taxonomy: Michener and Griswold (1994); Portman et al. (2019).

Subgenus Pseudoanthidium Friese s. s.

Pseudoanthidium (Pseudoanthidium) nanum (Mocsáry, 1881)* (20086) – Allegheny49 (BugGuide Image IDs: 1538244/1538247/1538248/1538249), Dauphin6, Lycoming8; 3 Jun6 – 28 Aug8 (201849).

Genus Stelis Panzer

Taxonomy: Parker and Bohart (1979); Mitchell (1962).

Subgenus Dolichostelis Parker and Bohart

Stelis (Dolichostelis) louisae Cockerell, 1911 – Bucks49 (BugGuide Image IDs: 1417130/1417131/1417132/1416293), Lehigh49 (BugGuide Image IDs: 747710/747711/747712); 28 Jul49 – 1 Aug49 (201749).

Subgenus Stelis Panzer s. s.

Stelis (Stelis) coarctatus Crawford, 191637 – Adams1,3, Sullivan37; 22 May1 – 23 Jul37 (20093).

Stelis (Stelis) foederalis Smith, 1854 – Huntingdon1; 17 May1 – 27 May1 (19991).

Stelis (Stelis) labiata (Provancher, 1888) – locations, dates, and year not reported37.

Stelis (Stelis) lateralis Cresson, 186437Adams3, Allegheny1, Columbia5, Erie9; 7 May3 – 5–7 Jul9 (20153,9).

Megachilini

Genus Coelioxys Latreille

Taxonomy: Mitchell (1962, 1980); Baker (1975); Rocha Filho and Packer (2016).

Subgenus Allocoelioxys Tkalců

Coelioxys (Allocoelioxys) coturnix Pérez, 1884* (20148) – Lancaster8, York8; 1 Jun8 – 21 Jul8 (20158).

Subgenus Boreocoelioxys Mitchell

Revision: Baker (1975).

Coelioxys (Boreocoelioxys) banksi Crawford, 1914 – Allegheny1, Centre1; 24 Aug1 (19961).

Coelioxys (Boreocoelioxys) moestus Cresson, 186410Adams3, Allegheny1, Blair1,2, Centre7, Lawrence1, Philadelphia1; 24 May3 – 15 Sep3 (20177).

Coelioxys (Boreocoelioxys) octodentatus Say, 182410Adams3, Allegheny1, Centre7, Dauphin1, Forest1, Lancaster3, Lehigh1, Philadelphia1,4; 26 May3 – 24 Aug1,4 (20163,7).

Coelioxys (Boreocoelioxys) porterae Cockerell, 190010 – Allegheny1, Centre1, Lehigh1; 25 Jun1 – 23 Jul1 (19541).

Coelioxys (Boreocoelioxys) rufitarsis Smith, 185410,37Adams3, Allegheny1, Beaver1, Berks1, Bradford8, Bucks1, Centre7, Erie1,2, Lehigh1, Monroe2, Philadelphia1, York1; 11 Jun3 – 25 Sep1 (20177).

Coelioxys (Boreocoelioxys) sayi Robertson, 189710,37Adams3, Allegheny1, Berks1, Bucks1,8, Centre1,7, Chester1, Columbia1, Crawford4, Cumberland1, Dauphin1, Delaware1,2, Erie1, Fayette1, Franklin6, Huntingdon1,2, Lancaster2, Lawrence1, Lehigh1, Monroe1, Montgomery1, Northampton6, Philadelphia1,2,4, Union8, York8; 29 May228 Sep8 (20177).

Subgenus Cyrtocoelioxys Mitchell

Key: Baker (1975).

Coelioxys (Cyrtocoelioxys) modestus Smith, 185437 – Allegheny1, Centre7, Lehigh1; Jun116–17 Aug7 (20177).

Subgenus Paracoelioxys Gribodo

Revision: Baker (1975 as Subgenus Schizocoelioxys Mitchell).

Coelioxys (Paracoelioxys) funerarius Smith, 185410,37Northampton6; 25 Jul6 (20106).

Subgenus Synocoelioxys Mitchell

Revision: Baker (1975).

Coelioxys (Synocoelioxys) alternatus Say, 183710,37Adams3, Huntingdon1,2, Lehigh6; 7 May6 – 2 Sep3 (20093).

Coelioxys (Synocoelioxys) hunteri Crawford, 1914 – Washington1; 13 Jul1 (19101).

Subgenus Xerocoelioxys Latreille s. s.

Revision: Baker (1975); Rocha-Filho and Packer (2016).

Coelioxys (Xerocoelioxys) immaculatus Cockerell, 1912 – Allegheny1, Philadelphia2; 8 Jul2 (20052).

Genus Megachile Latreille

Taxonomy: Mitchell (1934, 1935a; b, 1936a; b, 1937a; b; c, 1962); Parker (1978); Ivanochko (1979); Sheffield et al. (2011b).

Subgenus Callomegachile Michener

Megachile (Callomegachile) sculpturalis Smith, 1853* (19961) – Adams3, Bradford1, Bucks8, Centre1,6,7,44, Clinton1, Dauphin1,3,6, Erie1, Huntingdon1, Jefferson1,2,6, Lycoming44, Northampton6, Schuylkill6, Tioga1; 28 Jun3 – 15 Aug3 (20183).

Subgenus Chelostomoides Robertson

Revision: Mitchell (1937c).

Megachile (Chelostomoides) campanulae (Robertson, 1903)37Adams3, Allegheny1, Beaver1, Bucks8, Centre1,7, Dauphin1, Erie9, Huntingdon1,2, Jefferson6, Lancaster3, Monroe1, Philadelphia1,4; 15 May1 – 24 Aug1,4 (20183).

Megachile (Chelostomoides) exilis Cresson, 1872 – Adams3, Bucks8, Philadelphia1,4; 29 Jun3 – 23 Aug1,4 (20173).

Subgenus Eutricharaea Thomson

Taxonomy: Parker (1978); Mitchell (1980); Soltani et al. (2017).

Megachile (Eutricharaea) apicalis Spinola, 1808* (19961) – Bucks4, Carbon6, Dauphin1,6, Lancaster8, Lehigh6, Lycoming8, Northampton6, Schuylkill6, Union8, York8; 7 May6 – 28 Sep8 (20158).

Megachile (Eutricharaea) pusilla Pérez, 1884* (19461)37 – Centre1; 20 Jul1 (19461).

Megachile (Eutricharaea) rotundata (Fabricius, 1787)* (19461) – Adams3,6,8, Bradford1,6,8, Bucks4,8, Carbon6, Centre1,6,8,15,44, Clinton1,6, Dauphin1,6, Delaware1,4, Erie6,9, Franklin6, Lancaster3,6,8, Lehigh6, Lycoming8, Montgomery8, Northampton6, Philadelphia1,4, Schuylkill6, Union8, Westmoreland6, York8; 7 May6 – 9 Oct3 (20169).

Subgenus Leptorachis Mitchell

Taxonomy: Mitchell (1934).

Megachile (Leptorachis) petulans Cresson, 187837Berks6, Delaware1, Warren1; 30 Jul112 Aug6 (20086).

Subgenus Litomegachile Mitchell

Taxonomy: Mitchell (1935a); Bzdyk (2012).

Megachile (Litomegachile) brevis Say, 183737 – Adams1,3,8, Allegheny1, Bradford8, Bucks8, Centre1,15,44, Columbia5, Crawford4, Cumberland1, Dauphin1,6, Delaware1,4, Erie9, Franklin1, Huntingdon6, Juniata1, Lancaster5,15, Lycoming8, Montgomery1,7,8, Perry1, Philadelphia1,4, York8; 1 Jun8 – 15 Oct3 (20183).

Megachile (Litomegachile) mendica Cresson, 187837Adams3,8, Allegheny1, Berks2,6, Bradford8, Bucks1,4,8, Carbon6, Centre1,7,8,15,44, Chester1,8, Columbia2, Crawford6, Cumberland1, Dauphin1,2,6, Delaware1, Erie1,6,9, Fulton44, Huntingdon1,2,3,8, Jefferson6, Juniata3, Lancaster1,2,3,15, Lehigh1, Luzerne1, Lycoming8, Mifflin1, Monroe1, Montgomery1,2,7,8,44, Northampton4,6, Northumberland1, Perry4, Philadelphia1,2,4, Schuylkill6, Sullivan1, Union8, Westmoreland1, York8; 6 Mar116 Oct3 (20183).

Megachile (Litomegachile) texana Cresson, 187837 – Erie9, Lehigh1, Philadelphia1,2,4; 7 Jul1 – 25 Aug1,4 (20169).

Subgenus Megachile Latreille s. s.

Revision: Mitchell (1935b as Delomegachile).

Megachile (Megachile) centuncularis (Linnaeus, 1758)37 – Adams1, Allegheny1,2, Bradford8, Bucks4, Centre1, Dauphin1, Delaware1, Erie1,9, Franklin1, Huntingdon2, Montgomery8, Philadelphia1,4, York1,6; 15 May1 – 24 Sep1 (20169).

Megachile (Megachile) inermis Provancher, 188837Adams3, Centre1,7, Fayette1, Forest1, Huntingdon1; 24 Jun1 – 9 Sep1 (20177).

Megachile (Megachile) montivaga Cresson, 187837Adams3,8, Bradford1, Bucks4, Centre1,7, Chester8, Crawford1, Dauphin1,6, Erie9, Lancaster3, Lycoming8, Montgomery7, Pike1,4, Sullivan1, Washington6; 15 May6 – 28 Sep8 (20183).

Megachile (Megachile) relativa Cresson, 187837Adams3, Allegheny1, Blair1,2, Bradford8, Centre1,7,15, Clearfield1, Dauphin1,2,6, Erie9, Huntingdon1,2,3, Lancaster1,4, Lycoming8, Monroe1, Perry1, Somerset1,2, Sullivan1, Susquehanna8, Union8, Washington1, Wyoming4; 1 Jun3 – 3 Oct1 (20177).

Subgenus Megachiloides Mitchell

Revision: Mitchell (1936b).

Megachile (Megachilodes) integra Cresson, 1878 – Adams3, Bucks1, Dauphin1, Huntingdon1, Northampton6, Perry1, Philadelphia1; 5 May1 – 18 Sep1 (20123).

Subgenus Sayapis Titus

Revision: Mitchell (1937b).

Megachile (Sayapis) frugalis frugalis Cresson, 187237Adams3, Carbon6, Centre1, Dauphin1,6, Delaware4, Lehigh1, Northampton6; 26 May16 Aug6 (20173).

Megachile (Sayapis) inimica Cresson, 1872 sayi Cresson, 187837Adams3, Allegheny1, Bucks4,8, Centre1,7,8, Cumberland1, Dauphin1,6, Erie1, Huntingdon1, Lancaster3; 10 Jun6 – 28 Sep8 (20173,7).

Megachile (Sayapis) pugnata pugnata Say, 183737Adams3, Allegheny1, Beaver1, Centre1,7,15,44, Dauphin1, Huntingdon1,2,3, Lancaster3, Union1, Washington1; 29 May3 – 16–17 Aug7 (20183).

Subgenus Xanthosarus Robertson

Revision: Mitchell (1936a).

Megachile (Xanthosarus) addenda Cresson, 187837 – Adams1,3, Allegheny1, Centre15, Dauphin1,6, Erie9, Lehigh1; 16 May3 – 15 Jul1 (20159).

Megachile (Xanthosarus) frigida frigida Smith, 185337 – Centre1, Dauphin1, Erie1, Forest1, Lebanon1, Lycoming8, Monroe2, Montgomery8; 30 May1 - 20 Aug1 (20158).

Megachile (Xanthosarus) gemula gemula Cresson, 187837Adams3, Allegheny1, Bucks8, Centre1,7, Cumberland1, Dauphin1, Elk1, Huntingdon3, Lehigh1, Monroe1,2, Philadelphia1, Sullivan1,2; 30 Apr16 Sep3 (20183).

Megachile (Xanthosarus) ingenua Cresson, 187837 – locations, dates, and year not reported37.

Megachile (Xanthosarus) latimanus Say, 182337Adams3, Allegheny1, Bradford8, Bucks1, Carbon6, Centre1,7, Columbia2, Cumberland1,2, Dauphin1,2, Delaware1, Erie1,9, Franklin1, Huntingdon1, Lackawanna6, Lancaster2, Lehigh1, Monroe1, Philadelphia1, Schuylkill1, Sullivan1,2, Washington1, Westmoreland1, Wyoming1; 2–4 Jun9 – 1 Oct1 (20177).

Megachile (Xanthosarus) melanophaea melanophaea Smith, 185337Adams3, Allegheny1, Dauphin1, Sullivan1, Westmoreland6; 4 Jun114 Jul6 (20163).

Megachile (Xanthosarus) mucida Cresson, 1878 – Crawford6, Forest1; 19 Jul113 Aug6 (20086).

Osmiini

Genus Chelostoma Latreille

Subgenus Gyrodromella Michener

Taxonomy: Eickwort (1980); Buck et al. (2005); Müller (2015).

Chelostoma (Gyrodromella) rapunculi (Lepeletier, 1841)* (20159) – Erie9; 2–4 Jun9 – 9–11 Jun9 (20169).

Subgenus Prochelostoma Robertson

Taxonomy: Eickwort (1980); Buck et al. (2005).

Chelostoma (Prochelostoma) philadelphi (Robertson, 1891)37Adams3, Allegheny1, Bucks8, Centre6, Dauphin1, Delaware1, Erie9, Fayette1, Fulton1, Lycoming1, Montgomery1, Northumberland1, Perry1, Philadelphia1, Pike1, Westmoreland1; 18 Apr6 – 27 Jul1 (20183).

Genus Heriades Spinola

Subgenus Neotrypetes Robertson

Taxonomy: Michener (1938); Mitchell (1962).

Heriades (Neotrypetes) carinata Cresson, 1864 – Adams3, Allegheny1, Bucks8, Centre7,15, Chester8, Cumberland1, Erie1, Lancaster3, Lehigh1, Philadelphia1; 2 Jun114 Aug3 (20183).

Heriades (Neotrypetes) leavitti Crawford, 1913 – Adams3, Centre7; 4 Jun3 – 24–25 Jul7 (20177).

Heriades (Neotrypetes) variolosa (Cresson, 1872) – Adams3, Centre15, Montgomery8; 11 Jul8 – 15 Sep3 (20118).

Genus Hoplitis Klug

Taxonomy: Michener (1947); Mitchell (1962); Sedivy et al. (2013).

Subgenus Alcidamea Cresson

Hoplitis (Alcidamea) albifrons albifrons (Kirby, 1837) (tuberculata group) – Adams3, Somerset2; 24 Jun210 Jul3 (20153).

Hoplitis (Alcidamea) pilosifrons (Cresson, 1864) (producta group) – Adams3, Blair1,2, Bradford6, Centre7, Dauphin6, Delaware2, Huntingdon1,2, Lancaster3, Monroe4, Montgomery7, Northumberland1, Perry1, Philadelphia1,2, York8; 30 Apr3 – 18 Oct3 (20183).

Hoplitis (Alcidamea) producta producta (Cresson, 1864) (producta group)37Adams3, Allegheny1, Blair6, Bradford6,8, Butler, Centre6,7,8,15, Chester1, Clinton6, Crawford1, Cumberland1, Dauphin1,6, Delaware4, Erie6, Jefferson6, Lehigh1, Monroe4, Montgomery7, Philadelphia2, Union8, Washington6, York8; 4 May3 – 16–17 Aug7 (20183).

Hoplitis (Alcidamea) spoliata (Provancher, 1888) (tuberculata group) – Centre1,7, Crawford4, Dauphin1,6, Huntingdon1,2,8, Lehigh1, Lycoming8, Monroe2, Perry1; 27 May119–20 Aug4 (20177).

Hoplitis (Alcidamea) truncata truncata (Cresson, 1878) (truncata group) – Adams3, Bradford6, Clarion1, Cumberland1, Franklin1, Lehigh1, Northumberland6, York8; 1 Jun1 – 9 Aug1 (20158).

Subgenus Hoplitis Klug s. s.

Hoplitis (Hoplitis) anthocopoides (Schenck, 1853) (Annosmia−Hoplitis group)* (20123) – Adams3; 31 May3 – 14 Jun3 (20123).

Subgenus Robertsonella Titus

Hoplitis (Robertsonella) simplex (Cresson, 1864) – Bradford6, Bucks8, Dauphin6, Lancaster8, York8; 8 May6 – 16 Jun6 (20148).

Genus Osmia Panzer

Taxonomy: Sandhouse (1939); Mitchell (1962); Rust (1974).

Subgenus Diceratosmia Robertson

Revision: Michener (1949).

Osmia (Diceratosmia) conjuncta Cresson, 1864 – Adams3, Huntingdon8; 27 Apr8 – 15 Jun8 (20158).

Subgenus Helicosmia Thomson

Revision: Rust (1974 as Chalcosmia).

Osmia (Helicosmia) caerulescens (Linnaeus, 1758)* (19051)37Adams3, Allegheny1, Bradford1, Butler1, Centre1, Cumberland1, Dauphin1, Franklin1, Perry1, Philadelphia1, Pike1, Washington1,2; 10 Apr2 – 29 Aug1 (20173).

Osmia (Helicosmia) chalybea Smith, 1853 – Delaware1, Philadelphia2; 16 May2 – 22 Jun1 (19071).

Osmia (Helicosmia) coloradensis Cresson, 1878 – Bradford1; 13 Jun1 – 2 Jul1 (19391).

Osmia (Helicosmia) georgica Cresson, 187837Adams3, Allegheny1, Bradford8, Bucks8, Centre7, Dauphin1, Delaware1, Erie9, Huntingdon8, Lancaster3,8, Lycoming8, Montgomery4, Perry6, Susquehanna8, Union8, York1,8; 15 Apr821 Jul3 (20183).

Osmia (Helicosmia) texana Cresson, 1872 – Adams3, Allegheny1, Bradford8, Centre8, Cumberland6, Greene1, Huntingdon1, Lancaster8, Washington6; 25 May115 Sep8 (20183).

Subgenus Melanosmia Schmiedeknecht

Taxonomy: Rightmyer et al. (2010).

Osmia (Melanosmia) albiventris Cresson, 186437 – Centre1, Clarion6, Dauphin6, Huntingdon8, Lehigh1, Montgomery1, Philadelphia1, Tioga1, Union8, York8; 23 Apr13 Jul6 (20158).

Osmia (Melanosmia) atriventris Cresson, 186437Adams3, Allegheny1, Blair2, Bradford1,8, Bucks8, Centre7,8,15, Dauphin1, Delaware1,2, Huntingdon8, Lancaster8, Lycoming8, Monroe1, Montgomery7, Perry6, Philadelphia1,2, Pike1,4, Susquehanna8, Tioga1, Union8, York8; 29 Mar3 – 26–27 Jul7 (20183).

Osmia (Melanosmia) bucephala Cresson, 186437 – Adams1,3,8, Berks1, Bradford8, Bucks8, Centre2,6,7,15, Dauphin1,6, Delaware1, Erie9, Huntingdon1,3,6,8, Northumberland6, Pike1,4, Schuylkill1,2, Susquehanna8, Union8, Washington1, York8; 10 Apr1,3 – 4 Jul1 (20183).

Osmia (Melanosmia) collinsiae Robertson, 190537Adams3, Allegheny1, Bucks8, Centre7, Cumberland6, Perry6, York8; 12 Apr6 – 1 Jul1 (20177).

Osmia (Melanosmia) distincta Cresson, 186437Adams3, Cumberland6, Dauphin1,6, Delaware1, Huntingdon1,2, Luzerne1, Monroe4, Montgomery7, Perry6, Pike1,4, York8; 9 Apr21–30 Jun4 (20177).

Osmia (Melanosmia) felti Cockerell, 191137Adams3, Perry6; 12 Apr6 – 20 May3 (20093).

Osmia (Melanosmia) inspergens Lovell & Cockerell, 190737Centre7, Huntingdon8, Susquehanna8; 28 Apr8 – 24–25 May7 (20158).

Osmia (Melanosmia) proxima Cresson, 1864 – Sullivan1, York1; 27 Apr1 – 15 Aug1 (19411).

Osmia (Melanosmia) pumila Cresson, 186437 – Adams1,3, Bedford6, Blair1,2, Bradford1,6,8, Bucks2,8, Centre1,2,7,8,15, Chester1, Columbia5, Crawford1, Cumberland1,6, Dauphin1,6, Delaware1,2,4, Erie6,9, Franklin1,6, Greene6, Huntingdon1,8, Jefferson6, Lackawanna6, Lancaster1,3,8, Lehigh1, Lycoming6,8, Montgomery1,4, Montour6, Perry6, Philadelphia1,2, Pike1,4, Somerset1,2, Susquehanna8, Union8, Warren6, Washington1,6, York8; 13 Mar6 – 29 Jul6 (20183).

Osmia (Melanosmia) sandhouseae Mitchell, 1927 – Adams3, Huntingdon8; 23 Apr3 – 28 Apr8 (20153,8).

Osmia (Melanosmia) simillima Smith, 185337 – Adams1, Centre1, Cumberland1, Montgomery1, Philadelphia1, Tioga1; 8 May1 – 12 Jul1 (19091).

Osmia (Melanosmia) virga Sandhouse, 193937Adams3, Bucks8, Lancaster8, Lycoming8, Union8, York8; 15 Apr8 – 15 Jun8 (20158).

Subgenus Osmia Panzer s. s.

Revision: Rust (1974).

Osmia (Osmia) cornifrons (Radoszkowski, 1887)* (20023) – Adams3, Bradford8, Bucks8, Centre2,5,6,7,8,15, Cumberland6, Dauphin6, Erie9, Huntingdon8, Lancaster8, Lycoming6,8, Montgomery7, Susquehanna8, Union8, York8; 29 Mar3 – 29 Jul6 (20183).

Osmia (Osmia) lignaria lignaria Say, 183737 – Adams1,3, Allegheny1, Butler1, Cambria1, Centre1, Cumberland1, Dauphin1,4, Delaware1,2, Franklin1, Fulton1, Huntingdon1,3,8, Jefferson6, Juniata6, Lancaster8, Lehigh1, Montgomery1,2,7, Perry1, Philadelphia2, Somerset1, Washington1, Westmoreland1, York8; 31 Mar3 – 1 Sep1 (20173,7).

Osmia (Osmia) taurus Smith, 1873* (20083,6) – Adams3, Bradford8, Centre6,7,8, Clinton6, Cumberland6, Dauphin6, Erie9, Huntingdon8, Lancaster8, Lycoming8, Perry6, Susquehanna8, Union8, York8; 31 Mar3 – 29 Jul6 (20183).

Lithurginae

Lithurgini

Genus Lithurgus Berthold

Taxonomy: Snelling (1986).

Lithurgus chrysurus Fonscolombe, 1834* (20071) – Carbon6, Lehigh1,6, Northampton6; 7 Jul19 Aug6 (20096).

Andrenidae

Andreninae

Andrenini

Genus Andrena Fabricius

Taxonomy: Mitchell (1960); LaBerge (1967, 1969, 1971, 1973, 1977, 1980, 1985, 1987, 1989); Ribble (1967, 1968, 1974); LaBerge and Bouseman (1970, 1977); LaBerge and Ribble (1972, 1975); Bouseman and LaBerge (1978).

Subgenus Andrena Fabricius s. s.

Revision: LaBerge (1980).

Andrena (Andrena) carolina Viereck, 190925,36 – Centre1,6,7, Elk1, Luzerne1, Lycoming8, Philadelphia1,2, Pike1,4; 9 Apr115–16 Aug7 (20177).

Andrena (Andrena) clarkella (Kirby, 1802) – Forest1,25, Sullivan1,2; 30 Mar2 – 6 May1 (19831,2).

Andrena (Andrena) cornelli Viereck, 1907 – Adams3, Bucks8, Cumberland1, Erie9, Perry25, Philadelphia1,2,25, Schuylkill2; 4 May8 – 9–11 Jun9 (20163,9).

Andrena (Andrena) frigida Smith, 185336Union8, York8; 24 Apr8 - 28 Apr8 (20158).

Andrena (Andrena) macoupinensis Robertson, 190036Lancaster3, Philadelphia1, Pike1,4; 2 May1 – 30 May1,4 (20123).

Andrena (Andrena) mandibularis Robertson, 189236Adams3, Allegheny1,25, Bucks8, Centre1,7, Crawford1, Cumberland25, Dauphin1,25, Delaware2, Franklin1, Huntingdon3, Lycoming8, Montgomery1,25, Philadelphia1, Susquehanna8, Westmoreland1,25; 5 Mar113 Jun3 (20163,7).

Andrena (Andrena) milwaukeensis Graenicher, 190336 – Allegheny1,25, Centre1,3,5,7, Cumberland1,25, Dauphin1, Huntingdon8, Lycoming8, Monroe1,2, Somerset1,25, Susquehanna8, Westmoreland1, Wyoming1; 18 Apr1 – 22 Jun1 (20183).

Andrena (Andrena) rufosignata Cockerell, 190225 – Centre1, Clinton1, Forest1,25, Huntingdon8, Lycoming8, Sullivan1, Susquehanna8, Union8, Westmoreland1, York8; 15 Apr8 – 16 Jul1 (20158).

Andrena (Andrena) thaspii Graenicher, 1903 – Adams3, Allegheny1,25, Centre1,25, Huntingdon3, Westmoreland25; 1 May3 – 4 Jul1 (20123).

Andrena (Andrena) tridens Robertson, 190236Adams3, Bradford8, Centre1,7, Erie6,9, Franklin1, Huntingdon8, Jefferson6, Lancaster8, Lebanon1,25, Lycoming8, Perry1, Philadelphia1, Susquehanna8, Union8, Westmoreland1, York8; 13 Mar3 – 24 Jul6 (20173).

Subgenus Archiandrena LaBerge

Revision: LaBerge (1985).

Andrena (Archiandrena) banksi Malloch, 1917 – Bucks8, Susquehanna8; 28 Apr8 – 22 May8 (20158).

Andrena (Archiandrena) dimorpha Mitchell, 1960 – Philadelphia26; dates and year not reported26.

Subgenus Callandrena Cockerell s. l.

Revision: LaBerge (1967).

Andrena (Callandrena s. l.) aliciae Robertson, 1891 (aliciae group) – Allegheny1, Dauphin1, Fayette1; 6 Aug1 – 1 Sep1 (19401).

Andrena (Callandrena s. l.) asteris Robertson, 1891 (simplex group)36 – Allegheny1, Beaver1, Bucks8, Chester1, Columbia2, Dauphin1, Delaware1,2, Erie9, Lycoming1, Philadelphia1; 7 Sep1 – 29 Sep2 (20169).

Andrena (Callandrena s. l.) asteroides Mitchell, 1960 (simplex group) – Centre1; 5 Mar1 (19301).

Andrena (Callandrena s. l.) gardineri Cockerell, 1906 (gardineri group) – Adams3, Westmoreland1; 18 May121 May3 (20133).

Andrena (Callandrena s. l.) helianthi Robertson, 1891 (helianthi group) – Allegheny1, Chester1, Lackawanna6, Potter1, Westmoreland1; 21 Apr1 – 16 Sep1 (20086).

Andrena (Callandrena s. l.) krigiana Robertson, 1901 (krigiana group) – Dauphin1, Montgomery1,7, Perry1, Philadelphia1,2, Susquehanna8; 24 May1 – 3 Oct1 (20177).

Andrena (Callandrena s. l.) placata Mitchell, 1960 (simplex group) – Centre15, Erie9, Philadelphia1; 11–13 Sep9 – 19 Sep1 (20169).

Andrena (Callandrena s. l.) rudbeckiae Robertson, 1891 (melliventris group) – Huntingdon1,2; 12 Jul2 – 13 Jul1 (20051,2).

Andrena (Callandrena s. l.) simplex Smith, 1853 (simplex group)36 – Allegheny1, Bradford8, Bucks6, Chester1, Cumberland1, Dauphin6, Delaware1,2, Lycoming6,8, Philadelphia1, Wyoming1, York8; 8 Jun6 – 23 Sep2,8 (20158).

Subgenus Cnemidandrena Hedicke

Revision: Donovan (1977).

Andrena (Cnemidandrena) chromotricha Cockerell, 189936 – Allegheny1, Cambria36; 25 Aug36 (192536).

Andrena (Cnemidandrena) hirticincta Provancher, 188836 – Allegheny1, Beaver1, Centre7, Chester1, Cumberland1, Delaware1, Forest1, Mercer1, Monroe2, Philadelphia1, Tioga1; 20 Jun1 – 2 Oct1 (20177).

Andrena (Cnemidandrena) nubecula Smith, 1853 – Adams3, Allegheny1,2, Centre1,7,15, Clarion1, Cumberland1, Delaware1, Forest1, Luzerne1, Monroe1,2, Montgomery1, Union8, Wyoming1; 21 Jul128 Sep8 (20183).

Subgenus Conandrena Viereck

Revision: LaBerge (1986).

Andrena (Conandrena) bradleyi Viereck, 190726 – Bucks1, Centre6,7, Clinton1,26, Crawford2, Dauphin1,26, Delaware26, Huntingdon6, Lycoming8, Philadelphia2; 16 Apr131 May–1 Jun7 (20177).

Subgenus Derandrena Ribble

Revision: Ribble (1968).

Andrena (Derandrena) uvulariae Mitchell, 1960 – Westmoreland1; 18 May1 (19821).

Andrena (Derandrena) ziziaeformis Cockerell, 190836Bradford8, Centre7, Dauphin1, Delaware1, Huntingdon8, Lycoming8, Monroe1,2, Philadelphia1, Pike1,4, Union8, York1; 30 Apr115 Jun8 (20177).

Subgenus Euandrena Hedicke

Revisions: LaBerge and Ribble (1975); LaBerge (1977).

Andrena (Euandrena) algida Smith, 185336 – Centre1, Forest1, Montour6; 8 May1 – 23 Jun1 (20086).

Andrena (Euandrena) geranii Robertson, 189136 – Allegheny1,24, Bucks2,8, Centre1, Delaware1, Fayette1, Huntingdon3, Montgomery1, Philadelphia2, Union1,24, Westmoreland1,24; 22 Apr1 – 30 Jun1 (20068).

Andrena (Euandrena) nigrihirta (Ashmead, 1890)36 – Bucks1, Centre1, Huntingdon8, Monroe1, Susquehanna8; 28 Apr8 – 16 Jul1 (20158).

Andrena (Euandrena) phaceliae Mitchell, 196036 – Centre1; 22 May1 (19471).

Subgenus Gonandrena Viereck

Revision: LaBerge and Ribble (1972).

Andrena (Gonandrena) fragilis Smith, 1853 – Adams3, Cumberland1, Dauphin1, Huntingdon2, Lackawanna4, Lancaster1,30, Lehigh1, Montgomery1, Philadelphia1, Westmoreland1, York1; 28 May115 Jul4 (20134).

Andrena (Gonandrena) integra Smith, 1853 – Allegheny1,30, Bucks8, Delaware2, Huntingdon1, Philadelphia2, Westmoreland1,30; 7 Apr2 – 20 Jun1 (20078).

Andrena (Gonandrena) platyparia Robertson, 189536Adams3, Allegheny30, Bradford30, Centre1, Columbia1,5, Crawford1, Dauphin1, Lancaster30, Montgomery1; 19 May3 – 12 Jul1 (20173).

Subgenus Holandrena Pérez

Revision: LaBerge (1985).

Andrena (Holandrena) cressonii cressonii Robertson, 189136 – Adams1,3,8, Allegheny1,26, Blair2, Bradford8, Bucks8, Centre1,3,7, Chester1,2, Clinton6, Columbia5, Cumberland1,26, Dauphin1,6,26, Delaware1,2,4,26, Elk1, Erie9, Franklin1, Huntingdon2,8, Lancaster3,8, Lehigh1, Lycoming8, Monroe4, Montgomery1,2,7,26, Montour6, Northumberland26, Perry1,26, Philadelphia1,2,4,26, Union8, Warren2, Washington6, Westmoreland1,26, York1,8,26; 2 Apr3 – 1 Oct3 (20183).

Subgenus Iomelissa Robertson

Revision: LaBerge (1985). Monotypic.

Andrena (Iomelissa) violae Robertson, 189136Adams3, Allegheny1, Clinton1, Crawford1, Cumberland1,6, Dauphin1,6, Delaware1,26, Huntingdon8, Jefferson6, Lancaster8, Lycoming8, Monroe4, Northumberland26, Philadelphia1, Susquehanna8, Union8, Westmoreland1, York1,8; 31 Mar3 – 1–30 Jun4 (20183).

Subgenus Larandrena LaBerge

Revision: Ribble (1967).

Andrena (Larandrena) miserabilis Cresson, 187236 – Adams1,3, Allegheny1, Bucks1,8, Centre1,5,7,8, Chester1, Cumberland1, Dauphin1, Delaware1,2, Erie9, Forest1, Huntingdon8, Lancaster3,8, Lycoming8, Monroe1, Montgomery1,2, Philadelphia1,2, Pike1,2,4, Potter1, Tioga1, Union1,8, Westmoreland1, York1,8; 14 Feb19 Jul3 (20183).

Subgenus Leucandrena Hedicke

Revision: LaBerge (1987).

Andrena (Leucandrena) barbilabris (Kirby, 1802)36 – Bucks2, Butler27, Centre1, Cumberland1, Dauphin1,27, Delaware1,27, Fayette1, Lawrence1,27, Montgomery1,27, Northumberland27, Philadelphia1,27, Washington6; 30 Mar128 May6 (20086).

Andrena (Leucandrena) erythronii Robertson, 189136 – Allegheny1,27, Bucks8, Centre1, Crawford1, Huntingdon8, Jefferson6, Lycoming8, Northumberland1,27, Philadelphia2, Union1,27, Westmoreland1; 4 Apr1 – 6 Jun1 (20158).

Subgenus Melandrena Pérez

Revision: Bouseman and LaBerge (1979).

Andrena (Melandrena) barbara Bouseman and LaBerge, 1979 – Adams1,3, Bucks8, Centre1, Lancaster8, Westmoreland1, York8; 20 Mar3 – 17 May3 (20183).

Andrena (Melandrena) carlini Cockerell, 190136 – Adams1,3,8, Allegheny1,11, Beaver1,11, Berks1, Bradford8,11, Bucks8, Centre1,2,3,5,6,7,8,11,36, Chester1, Clinton1, Crawford1, Cumberland1, Dauphin1,6, Delaware1,2,11, Erie9, Franklin1, Huntingdon3,8, Jefferson6, Lancaster8, Lehigh1, Luzerne1,2,11, Lycoming8, Montgomery1,4,7, Northumberland1, Perry1,6, Philadelphia1,2,4,11, Pike1,4,11, Sullivan1, Susquehanna8, Union1,8, Wayne1, Westmoreland1,11, York1,8; 20 Mar3 – 1 Aug1 (20183).

Andrena (Melandrena) commoda Smith, 187936Adams3, Allegheny1,11, Berks1, Butler1, Carbon11, Centre1,11, Cumberland1, Dauphin1,11, Delaware2, Erie1, Lancaster5, Lehigh11, Monroe1, Montgomery1,7, Northumberland1, Philadelphia1,11, Pike1,2,11, Tioga1,11, York11; 3 Apr3 – 25 Jul1 (20183).

Andrena (Melandrena) confederata Viereck, 1917 – Adams3, Bucks8, Crawford1, Delaware1,2,11; 8 May8 – 6 Jun1 (20183).

Andrena (Melandrena) dunningi Cockerell, 1898 – Adams3, Allegheny1,11, Bradford8, Centre1,8, Chester1,11, Cumberland1, Dauphin1, Huntingdon8, Lancaster5,8, Lycoming8, Philadelphia1,2, Susquehanna8, Union8, York8; 20 Mar321 Jun3 (20183).

Andrena (Melandrena) hilaris Smith, 1853 – Adams3, Centre3, Chester1,11, Dauphin11, Delaware1,2,11, Philadelphia1,11; 21 Apr1 – 10 Aug1 (20183).

Andrena (Melandrena) illini Bouseman and La Berge, 1979 – Erie9, Westmoreland1; 18–20 May9 – 2 Jun1 (20169).

Andrena (Melandrena) nivalis Smith, 185336Adams3, Blair2, Bradford1,11, Carbon11, Centre1,7, Clinton1,6, Crawford1, Cumberland1,11, Dauphin1,2, Elk1, Huntingdon3, Lehigh1,11, Luzerne1, McKean2, Montgomery1,2,11, Northampton6, Perry1,6, Pike1,2,11, Sullivan1, Westmoreland1,11; 16 Apr6 – 26 Jul1 (20177).

Andrena (Melandrena) pruni Robertson, 189136Adams3, Allegheny1,11, Bedford2, Blair2, Bucks2,8, Centre1, Cumberland1, Dauphin1, Delaware1,2, Huntingdon2, Montgomery1,4,7, Philadelphia1, York1; 23 Mar3 – 20 Jun3 (20183).

Andrena (Melandrena) regularis Malloch, 191736 – Centre1, Clinton1,2,11; 25 Apr2 – 12 May1 (19661,2).

Andrena (Melandrena) sayi Robertson, 1891 – Lycoming8, Montgomery7, Philadelphia1; 28 Apr8 – 26–27 Jun7 (20177).

Andrena (Melandrena) vicina Smith, 185336Adams3, Allegheny11, Bradford11, Bucks8, Butler1, Centre1,7,11, Columbia5, Cumberland6, Dauphin1,6,11, Delaware1,2, Elk6, Erie9, Forest1, Huntingdon1,2,8, Jefferson6, Lancaster8, Lehigh1, Luzerne1, Lycoming8, Monroe1, Montgomery1,11, Northumberland1, Philadelphia1,4,11, Pike1,4, Westmoreland1; 5 Apr3 – 15–16 Aug7 (20183).

Subgenus Micrandrena Ashmead

Revision: Ribble (1968).

Andrena (Micrandrena) lamelliterga Ribble, 1968 (piperi group) – Beaver1; 5 Jun1 (19311).

Andrena (Micrandrena) melanochroa Cockerell, 1898 (piperi group) – Adams3, Allegheny1, York1; 8 May13 Jun3 (20093).

Andrena (Micrandrena) nigrae Robertson, 1905 (illinoiensis group) – Adams3, Allegheny1, Northumberland1, Philadelphia1, Washington6, York1; 24 Apr131 May3 (20183).

Andrena (Micrandrena) personata Robertson, 1897 (piperi group) – Bradford8, Bucks8, Centre7, Delaware2, Franklin1, Philadelphia1,4, York1; 6 Apr1 – 7 Jun1,8 (20167).

Andrena (Micrandrena) salictaria Robertson, 1905 (illinoiensis group)36 – Allegheny1, Franklin1, Huntingdon1, Westmoreland1; 9 Apr1 – 4 May1 (19661).

Andrena (Micrandrena) ziziae Robertson, 1891 (piperi group) – Allegheny1, Bucks8, Dauphin6, Tioga1, Washington6; 9 Apr6 – 28 May6 (20086). Notes. All specimens identified as A. ziziae should be reexamined as some may be attributable to A. vernalis, which has recently been resurrected from synonymy (see Portman et al., in press).

Subgenus Parandrena Robertson

Revision: LaBerge and Ribble (1972).

Andrena (Parandrena) nida Mitchell, 1960 – Butler30, Lawrence1,30; 27 Apr1 (19401).

Subgenus Plastandrena Hedicke

Revision: LaBerge (1969).

Andrena (Plastandrena) crataegi Robertson, 1893 (crataegi group)21,36Adams3, Allegheny1, Armstrong1, Bedford2, Butler1, Centre1,3,7, Crawford1, Cumberland1,2, Dauphin1,2, Delaware2, Erie1,9, Forest1, Fulton1, Huntingdon1,3, Indiana1, Lehigh1, Luzerne1, Monroe1, Montgomery1,7, Northumberland1, Pike1,2, Potter1, Snyder1, Somerset1, Susquehanna8, Tioga1, Westmoreland1; 22 Apr3 – 8 Aug1 (20173,7).

Subgenus Ptilandrena Robertson

Revision: LaBerge (1987).

Andrena (Ptilandrena) distans Provancher, 188836Adams3, Allegheny1,27, Centre1, Delaware1,2, Jefferson6, Philadelphia2, Union1,27; 17 Apr1 – 21 Jul1 (20173).

Andrena (Ptilandrena) erigeniae Robertson, 1891 – Adams3,8, Allegheny1,27, Bradford8, Bucks8, Butler1,27, Centre2,8, Crawford1, Cumberland6, Dauphin1,27, Delaware1,2,4,27, Franklin1,27, Huntingdon8, Lycoming8, Perry6, Philadelphia1, Pike1,4, Susquehanna8, Union8, Westmoreland1,27, York1,8,27; 15 Apr8 – 9 Jun2 (20158).

Subgenus Rhacandrena LaBerge

Revision: LaBerge (1977).

Andrena (Rhacandrena) brevipalpis Cockerell, 1930 – Adams3, Allegheny1,24, Berks24, Butler1, Centre7, Chester6, Cumberland1,2,24, Dauphin1,2,24, Fayette6, Northampton24, Northumberland24, Pike1,24, Somerset1,24, Westmoreland1,24; 14 May110 Oct6 (20163,7).

Andrena (Rhacandrena) robertsonii Dalla Torre, 189636Adams3, Bradford4,8, Bucks8, Cumberland1,24, Dauphin1, Delaware2, Franklin1, Huntingdon8, Lancaster8, Lycoming6, Montgomery7, Philadelphia1,24, Pike1,2, Potter1,24, Westmoreland1, York1; 26 Apr3 – 3 Aug4 (20177).

Subgenus Scaphandrena Lanham

Revision: Ribble (1974).

Andrena (Scaphandrena) arabis Robertson, 1897 (scurra group)36Adams3,8, Allegheny1, Bradford8, Bucks8, Carbon1, Centre8, Dauphin1, Delaware1, Huntingdon3,8, Lancaster8, Luzerne1,2, Lycoming8, Montgomery1,2, Philadelphia1,2, Union8, Washington1, Westmoreland1; 29 Mar1 – 21 Jun1 (20173).

Subgenus Scrapteropsis Viereck

Revision: LaBerge (1971).

Andrena (Scrapteropsis) alleghaniensis Viereck, 1907 (alleghaniensis group) – Bucks8, Dauphin1,22, Delaware2, Erie9, Monroe22, Philadelphia1,22; 10 May29–11 Jun9 (20169).

Andrena (Scrapteropsis) daeckei Viereck, 1907 (daeckei group) – Centre1, Luzerne22, Mifflin1; dates not reported1,22 (20071).

Andrena (Scrapteropsis) fenningeri Viereck, 1922 (imitatrix group) – Adams3, Philadelphia1,2, Venango6; 20 Apr3 – 9 May1 (20153).

Andrena (Scrapteropsis) ilicis Mitchell, 1960 (imitatrix group) – Philadelphia1,22, Westmoreland1; 16 May1 – 8 Jun1 (19501).

Andrena (Scrapteropsis) imitatrix Cresson, 1872 (imitatrix group)22,36Adams3,8, Allegheny1, Armstrong1, Beaver1, Bedford1, Blair2, Bradford8, Bucks2,8, Butler1, Centre1,5,7, Crawford1,6, Cumberland1, Dauphin1,6, Delaware1,2, Franklin1, Huntingdon1,8, Lancaster3,5,8, Luzerne1, Lycoming8, Montgomery1, Philadelphia1, Pike1,2, Susquehanna8, Union8, Westmoreland1, York1,8; 3 Mar3 – 30 Jun1 (20183).

Andrena (Scrapteropsis) morrisonella Viereck, 1917 (imitatrix group) – Allegheny1,22, Lancaster8, Lycoming8, Philadelphia1, Susquehanna8, York1,8; 24 Apr8 – Jul1 (20148).

Subgenus Simandrena Pérez

Revision: LaBerge (1989).

Andrena (Simandrena) nasonii Robertson, 189528,36Adams3,8, Allegheny1,28, Armstrong6, Bedford2, Blair2, Bradford1,6,8, Bucks8, Butler1, Centre1,2,5,7,8, Chester1,2,28, Clinton1, Columbia5, Crawford1, Cumberland1,6,28, Dauphin1,6,28, Delaware1,2,4,28, Erie9, Franklin1, Huntingdon2,3,8, Jefferson6, Lancaster3,8, Lycoming6,8, Mercer6, Monroe1,4, Montgomery1,2,7,28, Perry6, Philadelphia1,2,28, Pike1,4, Potter28, Susquehanna8, Union8, Warren6, Washington6,28, Westmoreland1, York8,28; 5 Mar3 – 1 Aug6 (20183).

Andrena (Simandrena) wheeleri Graenicher, 190428,36Adams3, Centre1; 16 Apr3 – 10 May1 (20083).

Subgenus Taeniandrena Hedicke

Revision: LaBerge (1989).

Andrena (Taeniandrena) wilkella (Kirby, 1802)* (19121)36Adams3, Allegheny1,28, Bedford6, Berks2,28, Bradford8, Bucks1,8,28, Butler1, Centre1,7,44, Chester8, Clarion28, Clinton1, Columbia5, Dauphin1, Delaware2, Erie1,28, Franklin1,28, Huntingdon1,2,8, Jefferson6, Lackawanna4, Lancaster3,5,8, Mifflin1, Montgomery8, Northampton6,28, Perry1, Philadelphia1,28, Schuylkill1,2, Union8, Westmoreland6, York1,8,28; 21 Apr124–25 Jul7 (20183).

Subgenus Thysandrena Lanham

Revision: LaBerge (1977).

Andrena (Thysandrena) bisalicis Viereck, 190836Adams3, Allegheny1,24, Armstrong6, Carbon24, Centre1, Clinton1,24, Crawford2, Cumberland1,24, Dauphin1,24, Delaware1,24, Erie9, Forest1,24, Lehigh1,24, Montgomery1,24, Northampton24, Washington1, Westmoreland1,24; 21 Mar3 – 10 Jun6 (20183).

Andrena (Thysandrena) w-scripta Viereck, 1904 – Allegheny1, Armstrong1,24, Bedford6, Carbon24, Cumberland1, Dauphin1,24, Huntingdon1, Lawrence24, Lehigh1,24, Luzerne1, Northampton24, Philadelphia1,2, Potter, Somerset1,24, York8; 15 Apr8 – 28 Aug6 (20158).

Subgenus Trachandrena Robertson

Revision: LaBerge (1973).

Andrena (Trachandrena) ceanothi Viereck, 1917 – Adams1,3, Allegheny1,23, Bedford2,23, Carbon23, Centre1,7, Cumberland1,23, Dauphin1,2, Franklin1, Lehigh1,23, Northampton23; 23 May3 – 28 Jun–1 Jul7 (20177).

Andrena (Trachandrena) forbesii Robertson, 189123,36Adams3,8, Allegheny1, Armstrong1, Bucks8, Centre1,5,7,8, Chester1, Crawford1, Cumberland1, Dauphin1,6, Delaware1,2, Franklin1, Huntingdon8, Lancaster3,8, Lycoming8, Mifflin1, Montgomery1, Philadelphia1, Pike1,2, Union1,8, Westmoreland1, York8; 20 Mar3 – 14 Jul1 (20183).

Andrena (Trachandrena) heraclei Robertson, 1897 – Adams3, Lancaster8, Philadelphia1,23, York8; 29 Mar3 – 21 Jun3 (20183).

Andrena (Trachandrena) hippotes Robertson, 189723Adams3, Allegheny1, Armstrong1, Bedford2, Centre2,3, Chester1, Cumberland1, Dauphin1,2, Delaware1,2, Franklin1, Huntingdon8, Lancaster8, Lycoming8, Monroe1, Northumberland1, Philadelphia1, Union8, Westmoreland1, York8; 5 Mar3 – 21 Sep1 (20183).

Andrena (Trachandrena) mariae Robertson, 1891 – Beaver1, Northumberland1, Philadelphia1; 10 May1 – 8 Jun1 (19511).

Andrena (Trachandrena) miranda Smith, 1879 – Bradford23, Crawford1, Cumberland1,23, Dauphin1, Franklin1, Montgomery1, Philadelphia1, York1; 28 Apr1 – 14 Jul1 (20071).

Andrena (Trachandrena) nuda Robertson, 189136Adams3, Allegheny1,23, Bucks1,2,8, Chester1,23, Crawford1, Dauphin1, Delaware1,2,23, Lancaster5, Philadelphia1,2,23, Westmoreland1, York1,8; 17 Apr8 – 25 Jun1 (20173).

Andrena (Trachandrena) rehni Viereck, 1907 – Allegheny1,23, Carbon23, Dauphin1,23, Delaware1,23, Lehigh1,2,23, Northampton23, Westmoreland1,23; 22 Jun1 – 29 Jul1 (19101).

Andrena (Trachandrena) rugosa Robertson, 189136Adams3, Allegheny1,23, Blair1,2, Bradford8, Bucks8, Butler23, Centre1,2,3,5,7, Crawford1, Cumberland1,23, Dauphin1,23, Delaware1, Erie9, Forest1,23, Franklin6, Lawrence1,23, Lycoming8, Montgomery1,23, Philadelphia1,23, Pike1,2,4, Potter1,23, Somerset23, Susquehanna8, Westmoreland1,23, York1; 20 Mar3 – 22 Jun1 (20173).

Andrena (Trachandrena) sigmundi Cockerell, 1902 – Beaver23, Clinton1,2,23, Delaware1; 25 Apr2 – 27 Apr1 (19661,2).

Andrena (Trachandrena) spiraeana Robertson, 189536Adams3, Allegheny1,23, Bedford2,23, Berks2, Bucks8, Carbon23, Centre1,7,23, Columbia1, Cumberland1,23, Dauphin1,23, Delaware1,2,23, Forest1, Huntingdon1, Lancaster1, Lehigh1,23, Montgomery23, Northampton23, Philadelphia1,23, Union8, Washington6, Westmoreland1,23, York1,8; 30 Apr8 – 13 Jul1 (20177).

Andrena (Trachandrena) virginiana Mitchell, 1960 – Bradford23, Centre1,5,7, Cumberland1,23, Lackawanna4, Lancaster5, Lehigh1; 25 Apr5 – 16–17 Aug7 (20177).

Subgenus Tylandrena LaBerge

Revision: LaBerge and Bouseman (1970).

Andrena (Tylandrena) erythrogaster (Ashmead, 1890)29Adams3, Allegheny1, Cumberland1, Dauphin1, Northumberland1, Philadelphia1, Potter1, Sullivan1; 1 May3 – 7 Jun1 (20143).

Andrena (Tylandrena) perplexa Smith, 185336Adams3,8, Allegheny1, Bradford8, Bucks6,8, Centre1,6, Cumberland1, Delaware1,2,4,29, Erie9, Fayette1,29, Huntingdon8, Indiana1, Jefferson6, Lackawanna1, Lancaster1,2,5, Lycoming8, Monroe1, Montgomery29, Perry1,29, Philadelphia1,4,29, Susquehanna8, Westmoreland1,29, York1,8,29; 5 Mar17 Jul6 (20183).

Andrena (Tylandrena) wilmattae Cockerell, 1906 – Allegheny1,29, Union1,29; 19 May1 – 2 Jul1 (19101).

Subgenus Xiphandrena LaBerge

Revision: LaBerge (1971). Monotypic.

Andrena (Xiphandrena) mendica Mitchell, 1960 – Allegheny1; 15 Jun1 (19371).

Panurginae

Calliopsini

Genus Calliopsis Smith

Taxonomy: Mitchell (1960); Shinn (1967).

Subgenus Calliopsis Smith s. s.

Calliopsis (Calliopsis) andreniformis Smith, 185336,43 – Adams1,3,6,8, Bedford6, Berks6, Blair6, Bradford1,8, Bucks1,8, Cambria6, Centre1,6,7,8,15, Chester6,8, Clarion6, Clearfield6, Crawford1,4,6, Cumberland, Dauphin1,6, Delaware1,4, Erie1,9, Franklin1,6, Fulton44, Huntingdon2,8, Jefferson2,6, Lackawanna, Lancaster3,6,8,15, Lehigh1,6, Lycoming8, Monroe6, Montgomery8, Perry6, Pike1,4, Somerset6, Union8, Warren6, Westmoreland1,6, York1,6,8; 12 May6 – 13 Oct3 (20183).

Perditini

Genus Perdita Smith

Taxonomy: Mitchell (1960); Timberlake (1954, 1958, 1960, 1968).

Subgenus Perdita Smith s. s.

Taxonomy: Timberlake (1958, 1960, 1968).

Perdita (Perdita) halictoides (halictoides group) Smith, 1853 – Union8; 15 Jun8 (20148).

Perdita (Perdita) octomaculata (Say, 1824) (octomaculata group) – Philadelphia1; 15 Sep1 (19011).

Protandrenini

Genus Protandrena Cockerell

Taxonomy: Mitchell (1960); Timberlake (1967, 1973, 1976); see also Scott et al. (2011).

Subgenus Heterosarus Robertson

Protandrena (Heterosarus) parvus (Robertson, 1892) – Cumberland47; dates and year not reported47.

Protandrena (Heterosarus) pauper (Cresson, 1878)47 – Lehigh1; 29 Jun1 – 12 Jul1 (19011).

Subgenus Metapsaenythia Timberlake

Protandrena (Metapsaenythia) abdominalis (Cresson, 1878)36 – locations, dates, and year not reported1.

Subgenus Pterosarus Timberlake

Protandrena (Pterosarus) aestivalis (Provancher, 1882) – Pike48; 22 Aug48 (189548) (AMNH_BEE00237743).

Protandrena (Pterosarus) andrenoides (Smith, 1853) – Adams3, Centre15; 18 Sep3 (20103).

Protandrena (Pterosarus) compositarum (Robertson, 1893) – Adams3, Chester1; 16 Jun3 – 18 Oct3 (20153).

Halictidae

Halictinae

Augochlorini

Genus Augochlora Smith

Subgenus Augochlora Smith s. s.

Augochlora (Augochlora) pura pura (Say, 1837)36 – Adams1,3,6, Allegheny1, Armstrong1, Beaver1,44, Bedford6, Berks1,2,6, Blair6, Bradford1,6,8, Bucks6,8, Butler1, Carbon6, Centre1,6,7,8,15,44, Chester1,6,8, Clarion6, Clearfield1,4,6, Clinton1,6, Columbia2,5, Crawford1,6, Cumberland1,6, Dauphin1,6, Delaware1,4, Elk1, Erie1,6,9, Fayette1, Forest1, Franklin6, Fulton44, Huntingdon1,2,3,8, Indiana1,6, Jefferson1,6, Juniata1,3,6,44, Lackawanna1,4,6, Lancaster1,3,5,6,8,15,44, Lawrence1, Lebanon1,4,6, Lehigh1,6, Luzerne2, Lycoming8, McKean1,4, Monroe6, Montgomery1,6,7,8,44, Northampton6, Perry1,6, Philadelphia1,2, Pike1,4, Schuylkill1,2, Somerset1,6, Sullivan1, Susquehanna8, Tioga1, Union8, Venango6, Washington1, Westmoreland1,6, York1,4,6,8; 13 Jan1 – 14 Nov1 (20183).

Genus Augochlorella Sandhouse

Taxonomy: Coelho (2004); Mitchell (1960); Ordway (1966).

Augochlorella aurata (Smith, 1853) (aurata group)36 – Adams1,3,8, Allegheny1, Armstrong6, Beaver44, Bedford6, Berks1,2,6, Blair6, Bradford1,6,8, Bucks1,8, Butler1, Cambria1,4,6, Cameron6, Carbon1, Centre1,3,6,7,8,15,44, Chester1,6,8, Clarion6, Clearfield6, Clinton1, Columbia1,2,5, Crawford1,4,6, Cumberland1,6, Dauphin1,6, Delaware1,4, Erie1,6,9, Fayette1, Franklin1,6, Huntingdon1,3,6,8, Indiana6, Jefferson6, Juniata6, Lackawanna4, Lancaster1,3,5,8,15,44, Lebanon4, Lehigh1,6, Luzerne1,2, Lycoming8, Monroe1,4, Montgomery1,4,7,8, Montour6, Northampton6, Northumberland1, Perry1,6, Philadelphia1,40, Pike1,4, Schuylkill4, Somerset1,6, Sullivan1, Susquehanna8, Tioga1, Union1,8, Venango1, Warren6, Washington1, Westmoreland1, York1,6,8; Feb1 – 5 Nov2 (20183).

Augochlorella persimilis (Viereck, 1910) (aurata group) – Adams3, Allegheny1, Bucks1, Clinton6, Delaware1,40, Huntingdon8, Jefferson6, Lehigh6; 29 May6 – 15 Sep3 (20163).

Genus Augochloropsis Cockerell

Taxonomy: Mitchell (1960).

Subgenus Paraugochloropsis Schrottky

Augochloropsis (Paraugochloropsis) metallica sensu lato (Fabricius, 1793) – Adams3, Armstrong6, Beaver1, Bradford6, Bucks8, Centre1,7,15, Chester1,8, Clinton1,6, Columbia5, Dauphin1,6, Delaware1,4, Elk1, Franklin6, Huntingdon1,2,3,8, Lackawanna2, Lebanon1, Lehigh1, Luzerne1, Lycoming6, Monroe1, Montgomery8, Northampton6, Perry1, Philadelphia1, Pike1, Union8, York1,6; 17 Apr3 – 21 Oct3 (20173). Notes. We can not rule out the possibility that the nominotypical subspecies of A. metallica does not occur in Pennsylvania. Thus, we present records for specimens not identified to the subspecies level here.

Augochloropsis (Paraugochloropsis) metallica (Fabricius, 1793) fulgida (Smith, 1853) – Centre7, Erie9; 18–20 May9 – 16–17 Aug7 (20177).

Augochloropsis (Paraugochloropsis) sumptuosa (Smith, 1853) – Chester1, Clinton6, Dauphin1, Elk6, Juniata6; 16 Apr12 Jul6 (20086).

Halictini s. l.

Genus Agapostemon Guerin-Meneville

Taxonomy: Mitchell (1960); Roberts (1972).

Subgenus Agapostemon Guerin-Meneville s. s.

Agapostemon (Agapostemon) sericeus (Förster, 1771) (sericeus group)42Adams3, Allegheny1, Armstrong1,6, Beaver1, Bradford8, Bucks1,8, Centre1,15,44, Columbia1, Cumberland1, Dauphin1,6, Delaware1, Elk1, Erie1,6, Fayette1, Huntingdon1,2,3, Lancaster3,8, Lehigh1, Lycoming8, Monroe1, Montgomery1,8,44, Northumberland1, Perry1, Philadelphia1,4, Somerset1, Union1,8, Warren6, Washington1, York1; 1 Apr1 – 30 Oct1 (20158).

Agapostemon (Agapostemon) splendens (Lepeletier, 1841) (splendens group)42Adams3, Allegheny1, Centre1, Crawford1, Delaware1, Erie1, Fulton44, Philadelphia1; 5 Jul3 – 29 Aug3 (20123).

Agapostemon (Agapostemon) texanus Cresson, 1872 (splendens group)42 – Adams1,3,8, Allegheny1, Armstrong1,6, Bedford6, Bucks8, Centre1, Chester6, Cumberland1, Dauphin6, Delaware1,4, Erie1,6, Franklin6, Huntingdon8, Lancaster3,8, Lehigh1, Lycoming8, Montgomery8, Northampton6, Northumberland1, Philadelphia1,4, Pike1,4, Schuylkill6, Union8, Westmoreland1, York6,8; 5 Apr3 – 26 Oct3 (20183).

Agapostemon (Agapostemon) virescens (Fabricius, 1775) (splendens group)42,36 – Adams1,3,8, Allegheny1, Armstrong6, Beaver1, Bedford6, Berks1,2, Bradford8, Bucks1,8, Butler1, Cambria6, Centre1,6,8,15,44, Chester6,8, Clarion6, Clearfield1,6, Clinton1,6, Columbia1,2,5, Crawford1,4, Cumberland1, Dauphin1,2,6, Delaware1,4, Elk6, Erie1,6,9, Fulton44, Greene1, Huntingdon1,2,8, Jefferson6, Juniata6, Lackawanna4,6, Lancaster1,3,4,5,6,8,15, Lehigh1,6, Luzerne1, Lycoming8, McKean6, Mifflin1, Montgomery1,7,8, Montour6, Northampton1, Perry1,6, Philadelphia1, Pike1,4, Somerset6, Sullivan1, Tioga1, Union8, Warren6, Washington1,6, Westmoreland1,4,6, York1,6,8; 22 Mar126 Oct3 (20183).

Genus Halictus Latreille

Revision: Mitchell (1960); Sandhouse (1941).

Subgenus Nealictus Pesenko

Halictus (Nealictus) parallelus Say, 1837 – Adams3, Allegheny1, Armstrong6, Bedford6, Bradford6, Bucks8, Clarion6, Crawford6, Dauphin6, Erie6, Juniata6, Lancaster3, Philadelphia1, Somerset6, Warren6, Wayne1, Westmoreland6; 30 Apr8 – 20 Aug6 (20133).

Subgenus Odontalictus Robertson

Halictus (Odontalictus) ligatus Say, 183736 – Adams1,3,6,8, Allegheny1,6, Beaver1,44, Bedford6, Berks2,6, Blair6, Bradford1,4,6,8, Bucks1,6,8, Butler1, Carbon1,6, Centre1,3,5,6,7,8,15,44, Chester6,8, Clarion6, Clearfield1,4, Clinton1,6, Columbia2,5, Crawford1,6, Cumberland1,6, Dauphin1,6, Delaware1,4, Elk6, Erie6,9, Forest1, Franklin6, Fulton44, Huntingdon1,2,8, Jefferson2,6, Juniata1,6,44, Lackawanna4,6, Lancaster1,2,3,4,5,6,8,15, Lebanon4, Lehigh1,6, Luzerne1,2, Lycoming1,8, McKean6, Monroe1,2,6, Montgomery1,7,8, Northampton6, Northumberland1, Perry1,4,6, Philadelphia1,4, Pike1,4, Schuylkill4,6, Snyder4, Somerset6, Sullivan4, Tioga1, Union8, Warren6, Washington6, York4,6,8; 11 Apr3 – 25 Oct3 (20183).

Subgenus Protohalictus Pesenko

Halictus (Protohalictus) rubicundus (Christ, 1791)36 – Adams1,3,8, Allegheny1, Armstrong6, Beaver44, Bedford6, Berks2,6, Bradford8, Bucks1,8, Butler1, Cambria6, Centre1,5,7,15,44, Chester6,8, Clarion6, Clinton1, Columbia5, Cumberland1,6, Dauphin1,4,6, Delaware1,4, Erie9, Forest1, Franklin1, Fulton44, Huntingdon3,8, Jefferson6, Juniata6, Lancaster3,5,8,15, Lehigh1, Luzerne1, Lycoming8, Monroe1,2, Montgomery1,7,8, Northampton6, Northumberland1, Perry1,6, Philadelphia1, Somerset6, Susquehanna1, Tioga1,4, Union8, Warren6, Westmoreland1, York8; 13 Apr116 Oct3 (20183).

Subgenus Seladonia Robertson

Halictus (Seladonia) confusus confusus Smith, 185336 – Adams1,3,6,8, Allegheny1, Beaver44, Bedford6, Berks6, Bradford1,6,8, Bucks1,4,6,8, Cambria1,4, Carbon1, Centre1,5,6,7,8,15,44, Chester8, Clinton1, Columbia5, Crawford1,4, Cumberland1, Dauphin1,6, Delaware1,4, Erie1,6,9, Huntingdon2,3,8, Jefferson2,6, Juniata6,44, Lackawanna4, Lancaster1,2,3,8,15, Lehigh1,6, Lycoming8, McKean6, Monroe1, Montgomery1,8, Northumberland1, Perry1, Philadelphia1,4, Pike1,4, Somerset6, Sullivan1, Susquehanna1, Tioga1, Union8, Wayne1, Westmoreland1,4,6, York1,6,8; 2 Apr6 – 5 Nov1 (20173,7).

Subgenus Vestitohalictus Blüthgen

Halictus (Vestitohalictus) tectus Radoszkowski, 1876* (20051,4) – Philadelphia1,4, Somerset6; 1 Aug6 – 24 Aug1,4 (20086).

Genus Lasioglossum Curtis

Taxonomy: Gibbs (2010, 2011, 2012); Gibbs et al. (2013); Knerer and Atwood (1964); McGinley (McGinley 1986, 2003); Mitchell (1960).

Subgenus Dialictus Robertson

Taxonomy: Gibbs (2010, 2011, 2012); Mitchell (1960).

Lasioglossum (Dialictus) abanci (Crawford, 1932) (viridatum group) – Adams3, Bradford1,8, Carbon1, Centre7,8, Franklin1, Huntingdon8, Lancaster8, Lehigh1, Lycoming8, Perry1, Union8; 23 Apr8 – 24 Aug8 (20173).

Lasioglossum (Dialictus) admirandum (Sandhouse, 1924) (viridatum group)36 – Adams1,3,8, Beaver44, Bradford1,8, Bucks8, Centre1,15,44, Chester1,8, Clearfield1, Clinton1, Crawford1, Cumberland1, Dauphin1, Delaware1, Erie9, Franklin1, Fulton44, Huntingdon3, Juniata1, Lancaster1,3,8,44, Lehigh1, Luzerne1, Mifflin1, Montgomery8, Perry1, Philadelphia1, Pike1, Sullivan1, Westmoreland1, York1,8; 2 Apr3 – 21 Oct3 (20173).

Lasioglossum (Dialictus) albipenne (Robertson, 1890)36Adams3, Bucks8, Centre7, Clinton1, Columbia5, Crawford4, Delaware1, Lancaster8, Lehigh1, Luzerne1, Montgomery1; 5 May119–20 Aug4 (20177).

Lasioglossum (Dialictus) anomalum (Robertson, 1892) – Adams3, Bucks8, Lycoming8, Pike1; 28 Apr8 – 15 Sep3 (20163).

Lasioglossum (Dialictus) apocyni (Mitchell, 1960) (viridatum group) – Centre7, Montgomery7, Westmoreland4; 31 May–1 Jun7 – 16–17 Aug7 (20177).

Lasioglossum (Dialictus) atwoodi Gibbs 2010 (viridatum group) – locations, dates, and year not reported18.

Lasioglossum (Dialictus) bruneri (Crawford, 1902)36Adams3, Bucks8, Centre8, Columbia5, Dauphin1, Delaware4, Erie9, Huntingdon8, Lycoming8, Philadelphia1,4, York8; 24 Apr8 – 21 Sep3 (20173).

Lasioglossum (Dialictus) callidum (Sandhouse, 1924) – Adams3, Centre5, Chester8, Delaware4, Lancaster3,5, Montgomery8; 13 Apr3 – 26 Oct3 (20183). Notes. Older records for L. versatum, especially pre-2010 determinations, may be attributable to L. callidum (see Gibbs 2010).

Lasioglossum (Dialictus) cattellae (Ellis, 1913) – Adams3, Bucks8; 17 Apr8 – 1 Aug8 (20088).

Lasioglossum (Dialictus) cephalotes (Dalla Torre, 1896) (cephalotes group) – locations, dates, and year not reported36.

Lasioglossum (Dialictus) coeruleum (Robertson, 1893)36Adams3, Bradford1, Bucks8, Butler1, Centre1,15,44, Clinton1, Dauphin1, Delaware1,4, Erie9, Fulton44, Huntingdon8, Jefferson6, Lancaster3, Lehigh1, Lycoming8, Monroe1, Montgomery1,7, Perry1, Philadelphia1, Susquehanna8, Union8, York8; 17 Apr1 – 4 Sep1 (20177).

Lasioglossum (Dialictus) coreopsis (Robertson, 1902) – Adams3, Bradford8, Bucks8, Pike1,4; 30 May1,418 Sep8 (20153).

Lasioglossum (Dialictus) cressonii (Robertson, 1890)18,36Adams3, Allegheny1, Bradford1,8, Bucks8, Centre1,7,8, Chester8, Clinton1, Crawford1, Cumberland1, Dauphin1, Delaware1,4, Erie9, Fulton1, Huntingdon1,2,8, Indiana1, Lackawanna1, Lancaster8, Lebanon4, Lehigh1, Lycoming8, Monroe1, Montgomery8, Perry1, Philadelphia1, Pike1, Susquehanna8, Union8, Washington1, York8; 15 Apr8 – 23 Oct3 (20173,7).

Lasiogl ossum (Dialictus) dreisbachi (Mitchell, 1960) – Centre53; 28 Sep53 (201853).

Lasioglossum (Dialictus) ellisiae (Sandhouse, 1924) (tegulare group)18Bucks8, Carbon17, Lehigh17, Erie9, Monroe17, Montgomery8, Northampton17, Somerset17, Union8; 9–11 Jun9 – 19 Aug8 (20169). Notes. Older records for L. tegulare, especially pre-2009 determinations, may be attributable to L. ellisiae (see Gibbs 2009).

Lasioglossum (Dialictus) ephialtum Gibbs, 2010 (viridatum group)18Adams3, Bradford8, Bucks8, Centre5,7,8, Erie9, Huntingdon8, Lancaster8, Lycoming8, Montgomery4,7,8, Philadelphia17, Union8, York8; 15 Apr8 – 9 Oct3 (20173,7).

Lasioglossum (Dialictus) georgeickworti Gibbs, 2011 (viridatum group) – Lancaster8, Lycoming8, Montgomery8, York8; 11 Jun8 – 24 Jul8 (20158).

Lasioglossum (Dialictus) gotham Gibbs, 2011 – Adams3, Bucks8,18, Centre8, Columbia5, Erie9, Huntingdon2,8,18, Lancaster3,5, Lycoming8, Union8, York8; 21 Mar3 – 26 Sep3 (20173).

Lasioglossum (Dialictus) heterognathus (Mitchell, 1960)18,36 – Centre1,7,8,36, Cumberland1, Huntingdon8, Lehigh1, Luzerne1, Lycoming8, Union8; 28 Apr1,828 Sep8 (20177).

Lasioglossum (Dialictus) hitchensi Gibbs, 201218Adams3,8, Bradford8, Bucks8, Centre5,7,8, Chester8, Columbia5, Delaware4, Erie9, Huntingdon8, Lancaster3,5,8, Lehigh1, Lycoming8, Montgomery4,8, Perry1, Tioga4, Union8, York8; 2 Apr326 Oct3 (20183).

Lasioglossum (Dialictus) illinoense (Robertson, 1892)18,36Adams3, Bucks8, Centre8, Chester8, Crawford1, Cumberland1, Dauphin1,17, Delaware1,4, Erie9, Franklin1, Huntingdon8, Lancaster5, Lehigh1, Lycoming8, Montgomery2,7,8, Union8, York8; 23 Apr8 – 19 Oct3 (20173,7).

Lasioglossum (Dialictus) imitatum (Smith, 1853)18,36 – Adams1,3,8, Berks2, Blair1,2, Bradford1,4,8, Bucks8, Centre1,5,7,8,15,44, Chester8, Clinton1, Columbia2,5, Crawford1, Cumberland1, Dauphin1,17, Delaware1,4, Erie9, Franklin1, Huntingdon1,2,8, Lackawanna4, Lancaster1,3,8, Lebanon1, Lehigh1, Luzerne2, Lycoming8, Mifflin1, Monroe1,2, Montgomery1,8, Northampton1, Perry1,4, Philadelphia1,4, Pike1, Sullivan1, Union1,8, York1,4,8; 18 Apr3 – 21 Oct3 (20173).

Lasioglossum (Dialictus) izawsum Gibbs, 2011 (platyparium group) – Westmoreland18; 29 May18 (194518).

Lasioglossum (Dialictus) katherineae Gibbs, 2011 (viridatum group) – Adams3; 10 Apr3 – 11 Sep3 (20143).

Lasioglossum (Dialictus) laevissimum (Smith, 1853)18Adams3, Bradford1,8, Bucks8, Centre1,5,7,8, Clinton1, Columbia5, Crawford1, Dauphin1, Delaware1, Huntingdon8, Lancaster3, Sullivan1, Susquehanna8, Union8; 25 Apr5 – 9 Oct3 (20183).

Lasioglossum (Dialictus) leucocomus (Lovell, 1908) (pilosum group) – Adams3, Bradford8, Bucks8, Centre7, Lancaster8, Montgomery8; 1 Jun8 – 19 Oct3 (20183). Notes. Older records for L. pilosum, especially pre-2010 determinations, may be attributable to L. leucocomus (see Gibbs 2010, 2011).

Lasioglossum (Dialictus) lineatulum (Crawford, 1906)18,36Adams3, Bradford1,8, Centre1,5,7,8,44, Clinton1, Columbia5, Crawford1, Dauphin1, Erie9, Lancaster8, Lehigh1, Lycoming8, Montgomery1, Northumberland1, Perry4, Philadelphia1, Pike1, Sullivan1, Union8; 17 Apr124 Aug8 (20177).

Lasioglossum (Dialictus) lionotus (Sandhouse, 1923) (cephalotes group) – Bradford8, Centre15, Dauphin1, Lebanon1, Lehigh1,4, Schuylkill1; 28 Apr115 Sep8 (20158).

Lasioglossum (Dialictus) marinum (Crawford, 1904) – Delaware1; 18 Jul1 (19011).

Lasioglossum (Dialictus) michiganense (Mitchell, 1960) (platyparium group) – Erie9, York8; 15 Apr8 – 18–20 May9 (20169).

Lasioglossum (Dialictus) nigroviride (Graenicher, 1911)18Bucks8, Centre1,7, Forest1, Jefferson2, Lackawanna1, Luzerne2, Lycoming8, Monroe1, Pike1; 28 Apr8 – 5 Sep2 (20177).

Lasioglossum (Dialictus) oblongum (Lovell, 1905) (viridatum group)36 – Bradford1, Bucks8, Centre1, Delaware1, Erie6, Forest1, Huntingdon8, Lackawanna1, Lancaster8, Lehigh1, Lycoming8, Monroe1, Sullivan1, Susquehanna8, Union8, Westmoreland1; 21 Apr8 – 23 Sep8 (20158).

Lasioglossum (Dialictus) obscurum (Robertson, 1892) (viridatum group)18,36 – Adams1,3, Bucks8, Centre1,8, Chester8, Columbia5, Cumberland1, Dauphin1, Delaware1,4, Erie9, Montgomery8, Northumberland1, Perry1, Westmoreland1, York8; 16 Apr128 Sep8 (20173).

Lasioglossum (Dialictus) oceanicum (Cockerell, 1916)18,36Adams3,8, Berks2, Bradford1, Bucks8, Centre1,3, Chester8, Clinton1, Crawford1, Cumberland1, Dauphin1, Delaware1, Erie9, Huntingdon1,8, Lancaster1,3, Lehigh1, Lycoming8, Monroe2,4, Montgomery1,8, Philadelphia1, York8; 10 May128 Sep8 (20165,9).

Lasioglossum (Dialictus) paradmirandum (Knerer & Atwood, 1966) (viridatum group)18Adams3, Berks2, Bradford8, Bucks8,17, Carbon1, Centre5,7, Huntingdon8, Lackawanna4, Lancaster5,8, Lehigh1, Lycoming8, Montgomery8,17, Union8, York8; 3 Apr3 – 18 Sep8 (20165,7).

Lasioglossum (Dialictus) perpunctatum (Ellis, 1913)36Adams3, Beaver44, Bradford3, Centre1,7,8,44, Erie9, Fulton44, Huntingdon8, Juniata44, Lancaster8,44, Monroe2, Union8; 18–20 May9 – 24 Aug8 (20177).

Lasioglossum (Dialictus) pilosum (Smith, 1853) (pilosum group)18,36 – Adams1,3,8, Beaver44, Berks1,2, Bradford8, Bucks1,4,8, Centre1,5,6,15,44, Chester1,8, Clinton1,6, Columbia2,5, Cumberland1, Dauphin1, Delaware1,4, Erie9, Franklin1,6, Fulton44, Huntingdon8, Lackawanna4, Lancaster3,5,6,8,15,44, Lehigh1, Luzerne1, Lycoming8, Monroe1, Montgomery1,2,8, Northumberland1, Perry1, Philadelphia1,4, Pike1, Sullivan1, Union8, York8; 23 Mar3 – 26 Oct3 (20183). Notes. Older records for L. pilosum, especially pre-2010 determinations, may be attributable to L. leucocomus (see Gibbs 2010, 2011).

Lasioglossum (Dialictus) planatum (Lovell, 1905) (viridatum group) – Adams3, Bradford8, Bucks8, Crawford4, Montgomery8; 6 May8 – 21 Oct3 (20148).

Lasioglossum (Dialictus) platyparium (Robertson, 1895) (platyparium group)18Adams3, Bradford8, Delaware4, Huntingdon8, Lancaster3,8, Lycoming8, Montgomery8, York8; 14 Apr3 – 23 Oct3 (20173).

Lasioglossum (Dialictus) pruinosum (Robertson, 1892) (pilosum group) – Beaver44, Centre44; dates not reported44 (2010 – 201244).

Lasioglossum (Dialictus) rozeni Gibbs, 2011 (platyparium group) – Adams3, Bucks8, Chester8, Montgomery8; 5 Apr3 – 26 Jul8 (20173).

Lasioglossum (Dialictus) simplex (Robertson, 1901)36 (platyparium group) – Centre1; Aug1 (19451).

Lasioglossum (Dialictus) smilacinae (Robertson, 1897)18Adams3, Erie9, Lehigh4, Lycoming8, Montgomery8, Union8, York8; 15 Apr8 – 6 Jul8 (20173).

Lasioglossum (Dialictus) subviridatum (Cockerell, 1938) (viridatum group) – Adams3, Bradford8, Bucks8, Centre7,8, Delaware4, Erie9, Huntingdon8, Lancaster8, Lycoming8, Montgomery8, Susquehanna8, Union8, York8; 15 Apr8 – 18 Oct3 (20177).

Lasioglossum (Dialictus) taylorae Gibbs, 2010 (viridatum group) – Bucks8, Delaware4, York8; 15 Apr8 – 13–26 Jul4 (20158).

Lasioglossum (Dialictus) tegulare (Robertson, 1890) (tegulare group)36Adams3,8, Berks2, Bradford1,8, Bucks8, Centre7,8,15,44, Chester8, Columbia5, Crawford4, Cumberland1, Dauphin1, Delaware1,4, Erie6,9, Franklin1, Fulton44, Huntingdon8, Juniata1,44, Lancaster3,8,44, Lehigh1, Luzerne1, Lycoming8,44, Montgomery1,8, Perry1, Philadelphia1,4, Schuylkill4, Somerset1, Susquehanna8, Union8, York8; 5 Apr3 – 24 Oct3 (20183). Notes. Older records for L. tegulare, especially pre-2009 determinations, may be attributable to L. ellisiae (see Gibbs 2009).

Lasioglossum (Dialictus) timothyi Gibbs, 2010 – Centre7, Lycoming8, Union8; 27 Apr8 – 29–30 Jun7 (20177).

Lasioglossum (Dialictus) trigeminum Gibbs, 2011 – Adams3,8, Bucks8, Centre7, Chester8, Delaware4, Erie9, Huntingdon8, Lancaster3,8, Lycoming8, Montgomery8, York8; 29 Mar3 – 19 Oct3 (20173,7).

Lasioglossum (Dialictus) versans (Lovell, 1905)18 (ruidosense group) – Adams3, Bradford1,8, Centre1,7,8,44, Columbia5, Dauphin1, Erie9, Huntingdon8, Lackawanna4, Lancaster8, Lycoming8, Pike1, Sullivan1, Susquehanna8, Union8, York8; 23 Apr8 – 24 Oct3 (20163,7,9).

Lasioglossum (Dialictus) versatum (Robertson, 1902)18,36 – Adams1,3,8, Beaver44, Bradford1,8, Bucks8, Centre1,5,7,8,44, Chester8, Clearfield1,4, Clinton1, Columbia5, Crawford1,4, Dauphin1, Delaware1,4, Erie9, Franklin1, Huntingdon2,3,8, Juniata3, Lackawanna1,4, Lancaster1,3,8, Lehigh1, Lycoming8, Monroe4, Montgomery1,7,8, Northumberland1, Perry1, Philadelphia1,4, Pike1,4, Schuylkill4, Sullivan1, Susquehanna8, Tioga4, Union8, Westmoreland1, York1,8; 29 Mar16 Nov3 (20173,7). Notes. Older records for L. versatum, especially pre-2010 determinations, may be attributable to L. callidum (see Gibbs 2010).

Lasioglossum (Dialictus) viridatum (Lovell, 1905) (viridatum group) – Adams3, Centre44, Erie6, Fulton44, Lancaster1,8,44, Lycoming8, Union8, York8; 15 Apr8 – 23 Jul6 (20158).

Lasioglossum (Dialictus) weemsi (Mitchell, 1960)18Adams3, Bradford8, Bucks8, Centre8, Chester8, Columbia5, Delaware4, Erie9, Huntingdon8, Lancaster3,8, Lycoming8, Monroe4, Montgomery8, Philadelphia17, Union8, York8; 21 Apr3 – 15 Oct3 (20173).

Lasioglossum (Dialictus) zephyrus (Smith, 1853)18,36Adams3,8, Beaver44, Blair2, Bradford1,8, Bucks8, Centre1,8, Chester8, Columbia2,5, Cumberland1, Dauphin1, Delaware1, Erie1,9, Fulton44, Huntingdon8, Lancaster3,5,8,44, Lehigh1, Lycoming8, Montgomery1,8, Northumberland1, Philadelphia1,4, Union1,8, York8; 10 Apr3 – 23 Oct3 (20173).

Subgenus Evylaeus Robertson

Taxonomy: Gibbs et al. (2013).

Lasioglossum (Evylaeus) cinctipes (Provancher, 1888)36 – Allegheny20, Centre1,5,7, Chester8, Cumberland1, Dauphin1, Erie9, Lehigh20, Susquehanna1,20, Tioga20, Union8, Westmoreland20; 28 Apr8 – 14 Oct1 (20177).

Subgenus Hemihalictus Cockerell

Revision: Gibbs et al. (2013).

Lasioglossum (Hemihalictus) birkmanni (Crawford, 1906) – Adams3, Allegheny20, Dauphin1, Erie20, Lackawanna4, Lancaster8, Union8; 23 Apr3 – 21 Jul8 (20173). Notes. Older records for L. macoupinense, especially pre-2013 determinations, are attributable to L. birkmanni (see Gibbs et al. 2013).

Lasioglossum (Hemihalictus) foxii (Robertson, 1895) – Adams3, Allegheny20, Bucks8, Centre7, Clinton20, Dauphin1, Erie20, Fayette20, Lehigh1, Lycoming8, Philadelphia4, Pike20, Potter20, Schuylkill2, Union8, Westmoreland20, York8; 2 Apr3 – 2 Jul8 (20173,7).

Lasioglossum (Hemihalictus) inconditum (Cockerell, 1916) – Susquehanna8; 6 May8 (20148).

Lasioglossum (Hemihalictus) macoupinense (Robertson, 1895) – Adams3, Allegheny20, Bucks1,8, Erie20, Susquehanna8; 30 Apr8 – 26 Jul3 (20148). Notes. Older records for L. macoupinense, especially pre-2013 determinations, are attributable to L. birkmanni (see Gibbs et al. 2013).

Lasioglossum (Hemihalictus) nelumbonis (Robertson, 1890) – Pike1,4; 29 May1,4 (20051).

Lasioglossum (Hemihalictus) pectinatum (Robertson, 1890) – Adams3, Bucks8,20, Lancaster20; 10 Jul8 – 20 Oct3 (20163).

Lasioglossum (Hemihalictus) pectorale (Smith, 1853) – Adams1,3, Allegheny20, Bucks1,2,8, Centre44, Columbia2, Cumberland1, Erie9, Franklin1, Huntingdon1,2,8, Lehigh1, Lycoming8, Philadelphia20, Westmoreland20; 16 Apr3 – 25 Aug3 (20173).

Subgenus Lasioglossum Curtis s. s.

Revision: McGinley (1986).

Lasioglossum (Lasioglossum) acuminatum McGinley, 1986 (forbesii group) – Adams3, Carbon32, Centre1,7,8,15, Clinton1, Huntingdon1,32, Lehigh1,32, Lycoming8, Monroe1,32, Northampton32, Pike1,2,32, Somerset1, Union8; 26 Apr3 – 7 Oct1 (20177).

Lasioglossum (Lasioglossum) athabascense (Sandhouse, 1933)36 – Adams1, Allegheny1,32, Bradford1, Carbon32, Centre1, Clearfield1,4, Clinton1, Crawford1, Cumberland1,32, Dauphin1,32, Lehigh1,32, Sullivan1, Wyoming32; 11 May1 – 29 Aug1 (20071,4).

Lasioglossum (Lasioglossum) coriaceum (Smith, 1853)36Adams3, Allegheny1,32, Beaver1,32,44, Bradford1,8, Bucks8, Butler1,32, Centre1,3,7,8,32, Clinton1, Crawford1,32, Cumberland1,32, Dauphin1,32, Delaware1,4,32, Elk1, Erie1,6,9,32, Fayette1,32, Forest1, Huntingdon1,8, Jefferson1, Lancaster1, Lehigh1,32, Lycoming8, Monroe1, Montgomery7,8, Northumberland1,32, Perry1, Pike1,4,32, Sullivan1, Susquehanna8, Tioga1, Union1,32, Washington1, Westmoreland1,32, York1,8,32; 16 Apr123 Oct3 (20173,7).

Lasioglossum (Lasioglossum) forbesii (Robertson, 1890) (forbesii group)36Adams3, Cumberland1, Fayette1,32, Westmoreland1,32; 16 Apr3 – 22 Jul1 (20153).

Lasioglossum (Lasioglossum) fuscipenne (Smith, 1853) – Adams3, Bradford1, Bucks8, Centre1, Crawford1, Cumberland1, Dauphin1,32, Delaware32, Huntingdon3, Montgomery7, York1,8,32; 30 Apr8 – 23 Oct3 (20177).

Subgenus Leuchalictus Warncke

Revision: McGinley (1986).

Lasioglossum (Leuchalictus) leucozonium (Schrenk, 1781)* (20071) – Adams1,3, Beaver44, Bradford1,4,8, Bucks8, Centre7,15,44, Crawford1,4, Erie9, Lackawanna4, Lancaster44, Lycoming8, Union8; 31 May–1 Jun7 – 19 Sep3 (20177).

Lasioglossum (Leuchalictus) zonulum (Smith, 1848)* (20023) – Adams3, Bradford1,8, Centre7, Crawford1, Erie6,9, Huntingdon3, Lackawanna4, Lycoming8, Monroe6, Susquehanna8; 8 May8 – 11–13 Sep9 (20177).

Subgenus Sphecodogastra Ashmead

Revision: Gibbs et al. (2013).

Lasioglossum (Sphecodogastra) comagenense (Knerer & Atwood, 1964) (fulvicorne group) – locations, dates, and year not reported46.

Lasioglossum (Sphecodogastra) oenotherae (Stevens, 1920) (lusorium group) – Cumberland33, Erie9, Lycoming8; 9–11 Jun9 – 24 Aug8 (20169).

Lasioglossum (Sphecodogastra) quebecense (Crawford, 1907) (fulvicorne group)36Adams3, Bradford8, Bucks8, Centre1,7, Chester6, Clinton20, Dauphin1, Delaware4, Erie9, Fayette1, Huntingdon8, Lancaster8, Monroe2,20, Montgomery7, Pike20, Susquehanna8, Union8, Westmoreland1,20, York8; 5 Apr3 – 13 Oct3 (20183).

Lasioglossum (Sphecodogastra) truncatum (Robertson, 1901) (calceatum group)36Adams3, Allegheny20, Beaver20, Bradford1,8, Bucks8, Centre1,5,6,7, Chester8, Columbia5, Crawford1, Huntingdon8, Lehigh20, Lycoming8, Montgomery8,20, Somerset20, Tioga20, Westmoreland20; 16 Apr3 – 19 Aug5 (20173,7).

Genus Sphecodes Latreille

Taxonomy: Mitchell (1960). Sphecodes is in particular need of revision (Gibbs et al. 2017a).

Sphecodes antennariae Robertson, 1891 (mandibularis group) – Adams3; 9 Oct3 (20083).

Sphecodes aroniae Mitchell, 1960 (ranunculi group)31Bucks8, Philadelphia2; 9 May8 – 26 May2 (20078).

Sphecodes atlantis Mitchell, 1956 (mandibularis group) – Adams3, Bradford8, Bucks8, Centre8, Erie1,2, Huntingdon8, Lancaster3, Lycoming8, Union8, York8; 11 Jun8 – 4 Sep3 (20158).

Sphecodes autumnalis Mitchell, 1956 (mandibularis group) – Susquehanna8; 28 Aug8 (20158).

Sphecodes banksii Lovell, 1909 (mandibularis group) – Adams3; 9 Oct3 (20083).

Sphecodes clematidis Robertson, 1897 (dichrous group) – Centre8, Susquehanna8; 24 Jul8 – 28 Aug8 (20158).

Sphecodes confertus Say, 1837 (confertus group) – Crawford2; 4 Jul2 (19602).

Sphecodes coronus Mitchell, 1956 (mandibularis group) – Adams3, Blair2, Centre7, Lancaster3, Monroe2, Philadelphia1; 16 May3 – 8 Oct3 (20177).

Sphecodes cressonii (Robertson, 1903) (mandibularis group)36 – Dauphin1, Lancaster8, Susquehanna8, Union8; 6 May8 – 23 Sep8 (20148).

Sphecodes dichrous Smith, 1853 (dichrous group)36 – Centre1,8, Chester8, Cumberland1, Dauphin1, Erie1, Lancaster1,3, Monroe2, Warren6; 28 Apr8 – 30 Jul3 (20158).

Sphecodes galerus Lovell & Cockerell, 1907 (mandibularis group) – Centre7, Lancaster3; 16 Jul3 – 16–17 Aug7 (20177).

Sphecodes heraclei heraclei Robertson, 1897 (dichrous group) – Bucks8, Centre1,7, Delaware1, Montgomery8; 29–30 Jun7 – 19 Aug1 (20177).

Sphecodes illinoensis (Robertson, 1903) (mandibularis group) – Tioga6; 27 Jun6 (20086).

Sphecodes levis Lovell & Cockerell, 1907 (mandibularis group) – Erie1; 4 Jun1 (19661).

Sphecodes mandibularis Cresson, 1872 (mandibularis group) – Blair2, Bucks8, Erie6, Lancaster8; 3 May8 – 21 Jul8 (20158).

Sphecodes minor Robertson, 1898 (dichrous group) – Bradford8, Dauphin1, Delaware2, Lancaster3, York1,8; 15 Apr8 – 31 Jul3 (20158).

Sphecodes pimpinellae Robertson, 1900 (mandibularis group) – Dauphin1, Erie1; 4 Jul1 (year not reported1).

Sphecodes prosphorus Lovell & Cockerell, 1907 (dichrous group) – Centre1,15,44, Lancaster3; 10 Jul3 – 14 Aug3 (20133).

Sphecodes ranunculi Robertson, 1897 (ranunculi group)36 – Bedford2, Bradford8, Centre8, Dauphin, Delaware2, Erie, Huntingdon1,8, Montgomery, Philadelphia2, Union8; 28 Apr8 – 14 Jul (20158).

Sphecodes smilacinae Robertson, 1897 (mandibularis group) – Adams3; 24 May3 (20113).

Sphecodes solonis Graenicher, 1911 (dichrous group) – Adams3; 28 Jul3 (20153).

Sphecodes townesi Mitchell, 1956 (mandibularis group) – Lycoming8; 15 Jun8 (20148).

Nomiinae

Dieunomiini

Genus Dieunomia Cockerell

Revision: Blair (1935).

Subgenus Dieunomia Cockerell s. s.

Dieunomia (Dieunomia) heteropoda heteropoda (Say, 1824) – Philadelphia1; 10 Sep1 (19711).

Nominiini

Genus Nomia Latreille

Taxonomy: Mitchell (1960); Ribble (1965)

Subgenus Acunomia Cockerell

Nomia (Acunomia) nortoni Cresson, 1868 – Allegheny1; dates and year not reported1.

Colletidae

Colletinae

Colletini

Genus Colletes Latreille

Taxonomy: Mitchell (1960); Stephen (1954).

Colletes aestivalis Patton, 1879 (aestivalis group) – Dauphin1, Monroe1, Montgomery45; 4 Jun1 – 4 Jul1 (19181).

Colletes americanus Cresson, 1868 (americanus group) – Bedford1, Delaware1, Philadelphia2, York1; 20 Sep1 – 8 Oct2 (19091).

Colletes compactus compactus Cresson, 1868 (compactus group)36Adams3, Allegheny1, Bedford1, Centre1, Clearfield4, Clinton1, Columbia1,2, Delaware2, Huntingdon1, Philadelphia2, Tioga1; 20 Aug1 – 8 Oct2 (20143).

Colletes eulophi Robertson, 1891 (simulans group)36 – Bedford1, Centre1; 20 Jul1 – 20 Sep1 (19541).

Colletes inaequalis Say, 1837 (inaequalis group)36Adams3, Allegheny1, Bradford8, Bucks8, Centre1, Cumberland1, Dauphin1,6, Erie1, Huntingdon1,3,8, Lancaster5, Lehigh1, Lycoming8, Montgomery1,2, Perry1, Philadelphia1,2,4, Washington1, York1,8; 17 Mar6 – 31 Aug2 (20183).

Colletes latitarsis Robertson, 1891 (latitarsis group)36Adams3, Allegheny1, Centre1, Dauphin1, Lancaster3,8, Montgomery8, Perry1, Venango1, Washington1; 13 Jun323 Sep8 (20148).

Colletes nudus Robertson, 1898 (nudus group)36Adams3, Dauphin1, Erie1, Franklin1; 20 May123 Jul3 (20153).

Colletes productus Robertson, 1891 (productus group) – Dauphin1, Philadelphia1,2; 27 Apr1 – 9 Jul2 (19092).

Colletes simulans Cresson, 1868 armatus Patton, 1879 (simulans group) – Centre1,7, Clinton1, Huntingdon1, Jefferson1,2, Monroe1,2; 23 Jul1 – 16 Sep1 (20177).

Colletes thoracicus Smith, 1853 (thoracicus group) – Dauphin6, Delaware4, Huntingdon1,2, Montgomery7; 14 May6 – 10 Jun1 (20177).

Colletes validus Cresson, 1868 (inaequalis group)36,45 – Centre1,7, Huntingdon1, Philadelphia2; 29 Apr224–25 May7 (20167).

Colletes willistoni Robertson, 1891 (willistoni group) – locations, dates, and year not reported36.

Hylaeinae

Hylaeini

Genus Hylaeus Fabricius

Taxonomy: Mitchell (1960); Snelling (1966, 1968, 1970).

Subgenus Hylaeus Fabricius s. s.

Revision: Snelling (1970).

Hylaeus (Hylaeus) annulatus (Linnaeus, 1758) – Bradford8, Centre7,15, Clarion6, Columbia5, Dauphin1, Erie9, Jefferson2, Lackawanna1, Monroe2, Sullivan1, Tioga1, Venango6, Warren6, Wyoming4; 6 Jun622 Aug5 (20177).

Hylaeus (Hylaeus) leptocephalus (Morawitz, 1871)* (20051,4) – Centre15, Erie9, Lancaster3, Northumberland1, Philadelphia1,4, Susquehanna8, York8; 7 Jun8 – 25 Aug1,4 (20158).

Hylaeus (Hylaeus) mesillae (Cockerell, 1896) cressoni (Cockerell, 1907) – Adams1,3,8, Blair2, Bradford4,8, Bucks8, Centre7,8,15, Dauphin1,4, Delaware1,4, Erie9, Franklin1, Huntingdon2, Lackawanna4, Lancaster3, Lebanon4, Lehigh1, Lycoming8, Monroe1,2, Montgomery2,8, Tioga4, Union8, York4; 30 Apr3 – 21 Oct3 (20183).

Hylaeus (Hylaeus) saniculae (Robertson, 1896) – Lehigh1; 29 Jun1 – 19 Jul1 (19031).

Subgenus Metziella Michener

Revision: Snelling (1968).

Hylaeus (Metziella) sparsus (Cresson, 1869)36Adams3, Bucks8; 9 May8 – 10 Jul3 (20153).

Subgenus Paraprosopis Popov

Revision: Snelling (1970).

Hylaeus (Paraprosopis) floridanus (Robertson, 1893) – Lycoming8; 19 Jun8 (20158).

Hylaeus (Paraprosopis) pictipes Nylander, 1852* (20159,19) – Crawford19, Erie9; 15 – 17 Jul192–4 Aug9 (20169,19).

Subgenus Prosopis Fabricius

Hylaeus (Prosopis) affinis (Smith, 1853)36 – Adams1,3, Allegheny1, Berks6, Bradford6,8, Centre1,6,7,15,44, Chester1,6, Clinton6, Crawford1, Dauphin1,6, Delaware1,4, Erie6, Franklin1, Fulton1, Huntingdon1,2,3, Jefferson6, Juniata6, Lackawanna4, Lancaster1,3, Lebanon4, Lehigh1,6, Lycoming8, Monroe1,2, Montgomery1, Northumberland1, Philadelphia1, Schuylkill4, Somerset6, Sullivan1, Susquehanna1, Tioga1, Venango1, Westmoreland1, Wyoming4, York1,8; 4 May3 – 25 Oct3 (20183).

Hylaeus (Prosopis) illinoisensis (Robertson, 1896) – Adams3, Bucks8; 19 May3 – 23 May8 (20163).

Hylaeus (Prosopis) modestus modestus Say, 183736 – Adams1,3, Allegheny1, Bedford6, Bradford1,6,8, Bucks1,6, Butler1, Centre1,7,15,44, Chester1,6, Clarion6, Clinton6, Crawford1, Cumberland1, Dauphin1,6, Delaware1,4, Elk1, Erie1,6,9, Franklin1, Huntingdon1,2,3, Jefferson2, Lackawanna4, Lancaster3,8,44, Lehigh1, Luzerne1,2, Monroe1, Montgomery1, Perry1,4, Philadelphia1, Pike1,4, Sullivan1, Tioga1,4,6, Union8, Westmoreland1, York4; 5 Apr36 Nov3 (20173,7).

Hylaeus (Prosopis) schwarzii (Cockerell, 1896) – Delaware4; dates not reported4 (20084).

Subgenus Spatulariella Popov

Taxonomy: Sheffield et al. (2011a).

Hylaeus (Spatulariella) hyalinatus Smith, 1842* (20094) – Adams3, Bradford8, Centre8, Dauphin4, Erie9, Lancaster8, Lebanon4, Lehigh48 (AMNH_BEE00270811), Lycoming8, Montgomery8, Union8, York8; 18–20 May9 – 28 Sep8 (20169).

Species excluded from the list of bees in Pennsylvania

Several valid bee species have been previously recorded from Pennsylvania, but their occurrence in the state is based on doubtful or erroneous identifications or otherwise cannot be confirmed. These species are listed below with brief comments.

Apidae

Nomada bisignata Say, 1824 (ruficornis group) – Donovall and vanEngelsdorp (2010) recorded this species as a new state record but indicated that no location or date data were available. The identity of this species is unclear since the original description could apply to numerous species and the type is likely not extant. Say (1824) did not specify its range below the country level. It is unclear how the identity of this species was determined by Donovall and vanEngelsdorp. It is possible that the specimen(s) reported in Donovall and vanEngelsdorp (2010) were/are located at the Department of Entomology, Academy of Natural Sciences (ANSP).

Andrenidae

Andrena (Scaphandrena) nigerrima Casad, 1896 – Westmoreland1; 18 May1 (19821). This species is not known to occur in the eastern United States (LaBerge and Bouseman 1977). The location of the specimen(s) reported under this name in Donovall and vanEngelsdorp (2010) cannot be confirmed.

Andrena (Scrapteropsis) kalmiae Atwood, 1934 (daeckei group) – Centre1; dates not reported1 (20071). Pennsylvania is outside of the known range of the species; the closest records are in Massachusetts and Connecticut (LaBerge 1971). It is possible that the specimen(s) reported in Donovall and vanEngelsdorp (2010) were/are located at PSUB. However, to our knowledge, they were not included in the Biddinger Laboratory Database under this name or as an updated entry.

Halictidae

Augochlorella gratiosa (Smith, 1853)36Berks6; 8 Jun6 (20096). Though this species was reported from Pennsylvania by Mitchell (1960), it has not been reported from north of North Carolina since the genus was revised by Coelho (2004). The specimen in the López-Uribe Laboratory was likely identified using keys in Mitchell (1960) and was not reexamined as part of this study. Until further evidence is available, we regard this species report as dubious.

Halictus (Odontalictus) poeyi Lepeletier, 1841 – Delaware1,4; 24 May1,4 (20071,4). Though this species is known from the eastern United States, it is only verified as far north as Maryland (Packer et al. 2016). It is also cryptic and generally considered indistinguishable from H. ligatus without genetic analysis (Carman and Packer 1996; Danforth et al. 1998). We are unable to confirm details about the identification methods used for this specimen.

Lasioglossum (Dialictus) halophitus (Graenicher, 1927) – Centre1; 3 Jul1 (20071). This species is a coastal salt march specialist and its occurrence north of Maryland has yet to be verified (Gibbs 2011). The location of the specimen(s) reported in Donovall and vanEngelsdorp (2010) cannot be confirmed.

Lasioglossum (Dialictus) subversans (Mitchell, 1960) – Centre1; 25 May1 – 13 Jul1 (20071). This species has a generally boreal distribution, and is only confirmed to extend south into the United States in Maine and Michigan (Gibbs 2010, 2011; Gibbs et al. 2017a). It is possible that the specimen(s) reported in Donovall and vanEngelsdorp (2010) were/are located at PSUB. However, to our knowledge, they were not included in the Biddinger Laboratory Database under this name or as an updated entry.

Lasioglossum (Dialictus) testaceum (Robertson, 1897) – Pike1; 3 Aug1 (19361). This species seems to occur primarily in the Great Plains, being more uncommon east of the Mississippi (Gibbs 2011). It is possible that the specimen(s) reported in Donovall and vanEngelsdorp (2010) were/are located at the Illinois Natural History Survey Biological Collections (INHS).

Colletidae

Colletes brimleyi Mitchell, 1951 (nudus group) – Lawrence1; 17 Jun1 (19611). This is a southeastern species that reaches its northern extent in the New Jersey Pine Barrens (Mitchell 1960). A record from Lawrence County is implausible. We were not able to locate the specimen in the PADA collection to confirm its identity.

Species expected to occur in Pennsylvania

The following species are anticipated to occur in Pennsylvania based on their known ranges. While they occur in neighboring regions, they have not yet been reported in the state.

Melittidae

Melitta americana (Smith, 1853) – This species is a Vaccinium L. specialist that ranges throughout the east and been confirmed from several surrounding states, including New Jersey (Mitchell 1960; Fowler 2016; Dibble et al. 2017).

Apidae

Triepeolus cressonii (Robertson, 1897) – This species is widespread across the eastern United States and has been reported from several surrounding states, including New Jersey (Mitchell 1962).

Andrenidae

Andrena (Parandrena) andrenoides (Cresson, 1878) – This Salix L. specialist is notably absent from the state based on its distribution across the eastern United States, which includes Ohio (Mitchell 1960; LaBerge and Ribble 1972).

Andrena (Cnemidandrena) canadensis Dalla Torre, 1896 – This Solidago L. specialist is notably absent from the state. It has been reported from several neighboring states, including Ohio, New Jersey, and New York, and is widely distributed in the eastern United States (Mitchell 1960; Fowler 2016; Dibble et al. 2017).

Andrena (Micrandrena) vernalis Mitchell, 1960 – This species has been treated as a synonym of Andrena (Micrandrena) ziziae Robertson, 1891 (piperi group) since Ribble (1968). In a recent study, Portman et al. (in press) have shown that A. vernalis is a valid species. Mitchell (1960) and Portman et al. (in press) record this species from several northeastern states, including neighboring New York and Ohio. Pennsylvanian specimens identified as A. ziziae should be reexamined to confirm their identity and future studies should consider the possibility that both species occur in the state.

Calliopsis (Verbenapis) nebraskensis Crawford, 1902 – This Verbena L. specialist has been recorded from the northeastern United States, including northern New Jersey (Shinn 1967; Fowler 2016). It is possible that it also occurs in Pennsylvania.

Perdita novaeangliae Viereck, 1907 – This rare species has reported from the northeastern United States, including Maryland and New Jersey, and is expected to occur in Pennsylvania (Mitchell 1960; North American Native Bee Collaborative 2017).

Perdita swenki Crawford, 1915 – This species has reported from the northeastern United States, including New York, and may occur in Pennsylvania (Mitchell 1960).

Halictidae

Sphecodes davisii (mandibularis group) Robertson, 1897 – This species is widespread across the eastern United States (Mitchell 1960; Dibble et al. 2017).

Sphecodes fattigi (mandibularis group) Mitchell, 1956 – This species occurs across the eastern United States (Mitchell 1960; Gibbs et al. 2017a).

Colletidae

Hylaeus (Spatulariiella) punctatus (Brullé, 1832)* – This exotic species has spread to a number of urban centers in Canada and the United States since its first detection in California in 1981 (Sheffield et al. 2011a; USGS Native Bee Laboratory 2019). It has been reported from the District of Columbia and New York (Ascher et al. 2006; Matteson et al. 2008). It seems likely that it may soon be found in Pennsylvania.

Data accessibility

Supplementary materials 117 are available for download as .csv files. Complete specimen records from databases may be available from the cited literature, future publications, or the contributors (upon request to the appropriate individuals) listed in Table 1.

Acknowledgements

We thank Beth Choate, Sam Droege, Carolyn Mahan, Hannah Stout, Kathryn Wholaver, Rachel Winfree for generously allowing access to specimen data and providing details about database organization. Additionally, we thank Shelby Fleischer, Lauren Gedlinske, Rufus Isaacs, and Keith Mason for allowing access to complete ICP specimen data. Thanks to Leo R. Donovall, III and Dennis vanEngelsdorp for their valuable advice and documents pertaining to the first checklist of bee species in the state. Emily Agar also shared insights about the initial Pennsylvanian checklist’s locality data. We are grateful to Sam Droege for specimen identification advice and for verifying the identifications of potentially dubious specimen records. We thank Karen Wright for sharing expertise about Melissodes species names and georeferencing protocols. Ryan Selking provided assistance with specimen record transcription and review, as well as additional insights about georeferencing and taxonomy. Thanks to Briana Ezray and Julie Urban for providing feedback on data organization, accessibility, and archiving. Members of the López-Uribe and Hines Laboratories, including Heather Hines, Stephania Sandoval Arango, Kristen Brochu, Ginamaría Román Echevarría, Chauncy Hinshaw, Laura Jones, Brooke Lawrence, and Avehi Singh, provided comments on the project and manuscript. Special thanks to members of the López-Uribe Laboratory for their assistance with collection and specimen database management. Tyler Jones, David Stupski, and Carolyn Trietsch provided additional feedback on figure design. We thank Sam Droege and Skyler Burrows for their critical review of the manuscript, and comments which clarified and improved the text. We also recognize the efforts of the many individuals who have collected, curated, and identified specimens and/or compiled their data, or otherwise contributed to our knowledge of bees in Pennsylvania over time.

SKK was supported by the Penn State Graduate Training Program in Integrative Pollinator Ecology, funded by the Penn State College of Agricultural Sciences’ Strategic Networking Initiative Program. This work was supported by the USDA National Institute of Food and Agriculture and Hatch Appropriations under Project #PEN04716.

References

  • Alexander BA, Schwarz M (1994) A catalog of the species of Nomada (Hymenoptera: Apoidea) of the world. The University of Kansas Science Bulletin 55: 239–270.
  • Ascher JS, Gambino P, Droege S (2006) Adventive Hylaeus (Spatulariella) Popov in the new world (Hymenoptera: Apoidea: Colletidae). Proceedings of the Entomological Society of Washington 108: 237–239.
  • Ascher JS, Kornbluth S, Goelet RG (2014) Bees (Hymenoptera: Apoidea: Anthophila) of Gardiners Island, Suffolk County, New York. Northeastern Naturalist 21(1): 47–71. https://doi.org/10.1656/045.021.0105
  • Ayala R, Griswold T (2012) Two new species of the bee genus Peponapis, with a key to the North and Central American species (Hymenoptera: Apidae: Eucerini). Revista Mexicana de Biodiversidad 83(2): 396–406. https://doi.org/10.22201/ib.20078706e.2012.2.1247
  • Baker JR (1975) Taxonomy of five Nearctic subgenera of Coelioxys (Hymenoptera: Megachilidae). The University of Kansas Science Bulletin 50: 49–730.
  • Bartomeus I, Ascher JS, Gibbs J, Danforth BN, Wagner DL, Hedtke SM, Winfree R (2013) Historical changes in northeastern US bee pollinators related to shared ecological traits. Proceedings of the National Academy of Sciences 110(12): 4656–4660. https://doi.org/10.1073/pnas.1218503110
  • Berenbaum M, Bernhardt P, Buchmann S, Calderone NW, Goldstein P, Inouye DW, Kevan P, Kremen C, Medellín RA, Ricketts T, Robinson GE, Snow AA, Swinton SM, Thien LB, Thompson FC (2007) Status of Pollinators in North America. The National Academies Press (Washington DC): 1–326. https://doi.org/10.17226/11761
  • Best LR, Marshall CJ, Red-Laird S (2019) Confirmed presence of the squash bee, Peponapis pruinosa (Say, 1837) in the state of Oregon and specimen-based observational records of Peponapis (Say, 1837) (Hymenoptera: Anthophila) in the Oregon State Arthropod Collection. Catalog: Oregon State Arthropod Collection, 3(3): 2–6. https://doi.org/10.5399/osu/cat_osac.3.3.4614
  • Blair BH (1935) The bees of the group Dieunomia. Journal of the New York Entomological Society 43: 201–215.
  • Broemeling DK (1988) A revision of the Nomadasubgenus Nomadita of North America. Pan-Pacific Entomologist 64: 321–344.
  • Broemeling DK, Moalif AS (1988) A revision of the Nomadasubgenus Pachynomada (Hymenoptera: Anthophoridae). The Pan-Pacific Entomologist 64: 201–227.
  • Brooks RW (1983) Systematics and bionomics of Anthophora: The bomboides group and species groups of the New World. University of California Publications in Entomology 98: 1–86.
  • Brumley RL (1965) A revision of the bee genus Epeolus of western America north of Mexico. MS Thesis. Utah State University (Logan).
  • Bouseman JK, LaBerge WE (1978) A revision of the bees of the genus Andrena of the Western Hemisphere. Part IX. Subgenus Melandrena. Transactions of the American Entomological Society 104: 275–389.
  • Buck M, Paiero SM, Marshall SA (2005) New records of native and introduced aculeate Hymenoptera from Ontario, with keys to eastern Canadian species of Cerceris (Crabronidae) and eastern Nearctic species of Chelostoma (Megachilidae). Journal of the Entomological Society of Ontario 136: 37–52.
  • Bzdyk EL (2012) A revision of the Megachilesubgenus Litomegachile Mitchell with an illustrated key and description of a new species (Hymenoptera, Megachilidae, Megachilini). Zookeys 221: 31–61. https://doi.org/10.3897/zookeys.221.3234
  • Cane JH, Tepedino VJ (2001) Causes and extent of declines among native North American invertebrate pollinators: detection, evidence, and consequences. Conservation Ecology 5(1): 1. https://doi.org/10.5751/ES-00252-050101
  • Carman GM, Packer L (1996) A cryptic species allied to Halictus ligatus Say (Hymenoptera: Halictidae) detected by allozyme electrophoresis. Journal of the Kansas Entomological Society 69(4): 168–176.
  • Černá K, Munclinger P, Vereecken NJ, Straka J (2017) Mediterranean lineage endemism, cold-adapted palaeodemographic dynamics and recent changes in population size in two solitary bees of the genus Anthophora. Conservation Genetics 18(3): 521–538. https://doi.org/10.1007/s10592-017-0952-8
  • Choate BA, Hickman PL, Moretti EA (2018) Wild bee species abundance and richness across an urban–rural gradient. Journal of Insect Conservation 22(3–4): 391–403. https://doi.org/10.1007/s10841-018-0068-6
  • Cockerell TDA (1908) Bees of the genus Nomada, belonging to the group of N. depressa Cresson. Entomological News 19: 323–324.
  • Colla SR, Ascher JS, Arduser M, Cane J, Deyrup M, Droege S, Gibbs J, Griswold T, Hall HG, Henne C, Neff J (2012) Documenting persistence of most eastern North American bee species (Hymenoptera: Apoidea: Anthophila) to 1990–2009. Journal of the Kansas Entomological Society 85(1): 14–23. https://doi.org/10.2317/JKES110726.1
  • Dainese M, Martin EA, Aizen M, Albrecht M, Bartomeus I, Bommarco R, Carvalheiro LG, Chaplin-Kramer R, Gagic V, Garibaldi LA, Ghazoul J, Grab H (2019) A global synthesis reveals biodiversity-mediated benefits for crop production. Science Advances 5: eaax0121. https://doi.org/10.1126/sciadv.aax0121
  • Daly HV (1973) Bees of the genus Ceratina in America north of Mexico (Hymenoptera: Apoidea). University of California Publications in Entomology 74: 1–114.
  • Danforth BN, van Dyke M (2015) The wild bees of New York: Our insurance policy against honey bee decline. New York Fruit Quarterly 23(4): 17–22.
  • Danforth BN, Mitchell PL, Packer L (1998) Mitochondrial DNA differentiation between two cryptic Halictus (Hymenoptera: Halictidae) species. Annals of the Entomological Society of America 91(4): 387–391. https://doi.org/10.1093/aesa/91.4.387
  • Danforth BN, Minckley RL, Neff JL, Fawcett F (2019) The Solitary Bees: Biology, Evolution, Conservation. Princeton University Press (Princeton): 1–472. https://doi.org/10.2307/j.ctvd1c929
  • DeBarros NB (2010) Floral resource provisioning for bees in Pennsylvania and the mid-Atlantic region. MS Thesis. The Pennsylvania State University (University Park).
  • Dibble AC, Drummond FA, Stubbs C, Veit M, Ascher JS (2017) Bees of Maine, with a state species checklist. Northeastern Naturalist 24(15): 1–49. https://doi.org/10.1656/045.024.m1503
  • Donovall LR, vanEngelsdorp D (2010) A Checklist of the Bees (Hymenoptera: Apoidea) of Pennsylvania. Journal of the Kansas Entomological Society 83(1): 7–24. https://doi.org/10.2317/JKES808.29.1
  • Donovan BJ (1977) A revision of North American bees of the Subgenus Cnemidandrena (Hymenoptera: Andrenidae). University of California Publications in Entomology 81: 1–107.
  • Dorchin A, López-Uribe MM, Praz CJ, Griswold T, Danforth BN (2018) Phylogeny, new generic-level classification, and historical biogeography of the Eucera complex (Hymenoptera: Apidae). Molecular Phylogenetics and Evolution 119: 81–92. https://doi.org/10.1016/j.ympev.2017.10.007
  • Eickwort GC (1980) Two European species of Chelostoma established in New York State (Hymenoptera: Megachilidae). Psyche 87: 315–323. https://doi.org/10.1155/1980/24124
  • Evans DL (1972) A revision of the subgenus Holonomada of the genus Nomada (Hymenoptera: Anthophoridae). The Wasmann Journal of Biology 30: 1–34.
  • Genung MA, Fox J, Williams NM, Kremen C, Ascher J, Gibbs J, Winfree R (2017) The relative importance of pollinator abundance and species richness for the temporal variance of pollination services. Ecology 98(7): 1807–1816. https://doi.org/10.1002/ecy.1876
  • Gibbs J (2009) Integrative taxonomy identifies new (and old) species in the Lasioglossum (Dialictus) tegulare (Robertson) species group (Hymenoptera, Halictidae). Zootaxa 2032: 1–38. https://doi.org/10.11646/zootaxa.2032.1.1
  • Gibbs J (2012) Two Replacement Names for North American Lasioglossum (Dialictus) (Hymenoptera: Halictidae). Journal of the Kansas Entomological Society 85(3): 259–261. https://doi.org/10.2317/JKES120424.1
  • Gibbs J, Dathe HH (2017) First records of Hylaeus (Paraprosopis) pictipes Nylander, 1852 (Hymenoptera: Colletidae) in North America. Check List 13(3): 1–6. https://doi.org/10.15560/13.3.2116
  • Gibbs J, Packer L, Dumesh S, Danforth BN (2013) Revision and reclassification of Lasioglossum (Evylaeus), L. (Hemihalictus) and L. (Sphecodogastra) in eastern North America (Hymenoptera: Apoidea: Halictidae). Zootaxa 3672: 1–116. https://doi.org/10.11646/zootaxa.3672.1.1
  • Gibbs J, Ascher JS, Rightmyer MG, Isaacs R (2017a) The bees of Michigan (Hymenoptera: Apoidea: Anthophila), with notes on distribution, taxonomy, pollination, and natural history. Zootaxa 4352(1): 1–160. https://doi.org/10.11646/zootaxa.4352.1.1
  • Gibbs J, Joshi NK, Wilson JK, Rothwell NL, Powers K, Haas M, Gut L, Biddinger DJ, Isaacs R (2017b) Does passive sampling accurately reflect the bee (Apoidea: Anthophila) communities pollinating apple and sour cherry orchards?. Environmental Entomology 46(3): 579–588. https://doi.org/10.1093/ee/nvx069
  • Giles V, Ascher JS (2006) A survey of the bees of the Black Rock Forest preserve, New York (Hymenoptera: Apoidea). Journal of Hymenoptera Research 15(2): 208–231.
  • Goldstein PZ, Ascher JS (2016) Taxonomic and behavioral composition of an island fauna: A survey of bees (Hymenoptera: Apoidea: Anthophila) on Martha’s Vineyard, Massachusetts. Proceedings of the Entomological Society of Washington 118: 37–92. https://doi.org/10.4289/0013-8797.118.1.37
  • Gonzalez VH, Griswold TL (2013) Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal of the Linnean Society 168: 221–425. https://doi.org/10.1111/zoj.12017
  • Grab H, Branstetter MG, Amon N, Urban-Mead KR, Park MG, Gibbs J, Blitzer EJ, Poveda K, Loeb G, Danforth BN (2019) Agriculturally dominated landscapes reduce bee phylogenetic diversity and pollination services. Science, 363(6424): 282–284. https://doi.org/10.1126/science.aat6016
  • Hurd PD (1961) A synopsis of the carpenter bees belonging to the Subgenus Xylocopoides Michener (Hymenoptera; Apoidea). Transactions of the American Entomological Society 87: 247–257.
  • Hurd PD (1979) Superfamily Apoidea. In: Krombein KV, Hurd PD, Smith DR, Burks BD (Eds) Catalog of Hymenoptera in America North of Mexico. Smithsonian Institution Press, (Washington DC), 1741–2209.
  • Hurd PD, Linsley EG (1951) The melectine bees of California. Bulletin of the California Insect Survey 1(5): 119–140.
  • Hurd PD, Linsley EG (1964) The squash and gourd bees, genera Peponapis Robertson and Xenoglossa Smith, inhabiting America north of Mexico (Hymenoptera: Apoidea). Hilgardia 35: 384–472. https://doi.org/10.3733/hilg.v35n15p375
  • Ivanochko M (1979) Taxonomy, biology and alfalfa pollinating potential of Canadian leaf-cutter bees – genus Megachile Latreille (Hymenoptera: Megachilidae). MS Thesis. McGill University (Montreal).
  • Jamieson MA, Carper AL, Wilson CJ, Scott VL, Gibbs J (2019) Geographic biases in bee research limits understanding of species distribution and response to anthropogenic disturbance. Frontiers in Ecology and Evolution 7(194): 1–8. https://doi.org/10.3389/fevo.2019.00194
  • Jean RP (2010) Studies of bee diversity in Indiana: The influence of collection methods on species capture, and a state checklist based on museum collections. PhD Thesis. Indiana State University (Terre Haute).
  • Knerer G, Atwood CE (1964) Further notes on the genus Evylaeus Robertson (Hymenoptera: Halictidae). The Canadian Entomologist 96: 957–962. https://doi.org/10.4039/Ent96957-7
  • Koh I, Lonsdorf EV, Williams NM, Brittain C, Isaacs R, Gibbs J, Ricketts TH (2016) Modeling the status, trends, and impacts of wild bee abundance in the United States. Proceedings of the National Academy of Sciences 113(1): 140–145. https://doi.org/10.1073/pnas.1517685113
  • LaBerge WE (1955) Bees of the genus Anthedonia Michener in North America. Journal of the Kansas Entomological Society 28: 132–135.
  • LaBerge WE (1956a) A revision of the bees of the genus Melissodes in North and Central America. Part I. (Hymenoptera, Apidae). The University of Kansas Science Bulletin 37: 911–1194. https://doi.org/10.5962/bhl.part.24549
  • LaBerge WE (1956b) A revision of the bees of the genus Melissodes in North and Central America. Part II (Hymenoptera, Apidae). The University of Kansas Science Bulletin 38: 533–578. https://doi.org/10.5962/bhl.part.9821
  • LaBerge WE (1961) A revision of the bees of the genus Melissodes in North and Central America. Part III (Hymenoptera, Apidae). The University of Kansas Science Bulletin 42: 283–663. https://doi.org/10.5962/bhl.part.9821
  • LaBerge WE (1967) A revision of the bees of the genus Andrena of the Western Hemisphere. Part I. Callandrena (Hymenoptera: Andrenidae). Bulletin of the University of Nebraska State Museum 7: 1–316.
  • LaBerge WE (1969) A revision of the bees of the genus Andrena of the Western Hemisphere Part II. Plastandrena, Aporandrena, Charitandrena. Transactions of the American Entomological Society 95: 1–47.
  • LaBerge WE (1971) A revision of the bees of the genus Andrena of the Western Hemisphere. Part IV. Scrapteropsis, Xiphandrena and Raphandrena. Transactions of the American Entomological Society 97: 441–520.
  • LaBerge WE (1973) A revision of the bees of the genus Andrena of the Western Hemisphere. Part VI. Subgenus Trachandrena. Transactions of the American Entomological Society 99: 235–371.
  • LaBerge WE (1977) A revision of the bees of the genus Andrena of the Western Hemisphere. Part VIII. Subgenera Thysandrena, Dasyandrena, Psammandrena, Rhacandrena, Euandrena, Oxyandrena. Transactions of the American Entomological Society 103: 1–143.
  • LaBerge WE (1980) A revision of the bees of the genus Andrena of the Western Hemisphere. Part X. Subgenus Andrena. Transactions of the American Entomological Society 106: 395–525.
  • LaBerge WE (1985) A revision of the bees of the genus Andrena of the Western Hemisphere, Part XI. Minor subgenera and subgeneric key. Transactions of the American Entomological Society 111: 441–567.
  • LaBerge WE (1987) A revision of the bees of the genus Andrena of the Western Hemisphere. Part XII. Subgenera Leucandrena, Ptilandrena, Scoliandrena, and Melandrena. Transactions of the American Entomological Society 112: 191–248.
  • LaBerge WE (1989) A revision of the bees of the genus Andrena of the Western Hemisphere. Part XIII. Subgenera Simandrena and Taeniandrena. Transactions of the American Entomological Society 115: 1–56.
  • LaBerge WE, Bouseman JK (1970) A revision of the bees of the genus Andrena of the Western Hemisphere. Part III. Tylandrena. Transactions of the American Entomological Society 96: 543–605.
  • LaBerge WE, Bouseman JK (1977) On the systematic position of three black Andrena from Western North America (Hymenoptera: Andrenidae). Journal of the Kansas Entomological Society 50(4): 601–612.
  • LaBerge WE, Ribble DW (1972) A revision of the bees of the genus Andrena of the Western Hemisphere. Part IV. Gonandrena, Geissandrena, Parandrena, Pelicandrena. Transactions of the American Entomological Society 98: 271–358.
  • LaBerge WE, Ribble DW (1975) A revision of the bees of the genus Andrena of the Western Hemisphere. Part VII. Subgenus Euandrena. Transactions of the American Entomological Society 101(3): 371–446.
  • LeBuhn G, Droege S, Connor EF, Gemmill‐Herren B, Potts SG, Minckley RL, Griswold T, Jean R, Kula E, Roubik DW, Cane J, Wright K, Frankie G, Parker F (2013) Detecting insect pollinator declines on regional and global scales. Conservation Biology 27(1): 113–120. https://doi.org/10.1111/j.1523-1739.2012.01962.x
  • Linsley EG (1939) A revision of the nearctic Melectinae (Hymenoptera, Anthophoridae). Annals of the Entomological Society of America 32(2): 429–468. https://doi.org/10.1093/aesa/32.2.429
  • Martins KT, Normandin É, Ascher JS (2017) Hylaeus communis (Hymenoptera: Colletidae), a new exotic bee for North America with generalist foraging and habitat preferences. The Canadian Entomologist 149: 377–390. https://doi.org/10.4039/tce.2016.62
  • McCabe LM, Chesshire PR, Smith DR, Wolf A, Gibbs J, Griswold TL, Wright KW, Cobb NS (2020) Bee species checklist of the San Francisco Peaks, Arizona. Biodiversity Data Journal 8: e49285. https://doi.org/10.3897/BDJ.8.e49285
  • McGrady CM, Troyer R, Fleischer SJ (2019) Wild Bee Visitation Rates Exceed Pollination Thresholds in Commercial Cucurbita Agroecosystems. Journal of Economic Entomology toz 295: 1–13. https://doi.org/10.1093/jee/toz295
  • McGinley RJ (1986) Studies of Halictinae (Apoidea: Halictidae), I: Revision of New World Lasioglossum Curtis. Smithsonian Contributions to Zoology 429: 1–294. https://doi.org/10.5479/si.00810282.429
  • McGinley RJ (2003) Studies of Halictinae (Apoidea: Halictidae), II: Revision of Sphecodogastra Ashmead, floral specialists of Onagraceae. Smithsonian Contributions to Zoology 610: 1–55. https://doi.org/10.5479/si.00810282.610
  • McIlroy D (2017) Packaged for R by Ray Brownrigg, Thomas P Minka and transition to Plan 9 codebase by Roger Bivand. mapproj: Map Projections. R package version 1.2-5. https://CRAN.R-project.org/package=mapproj
  • McKinney M (2016) Bee Natural History, Diversity, and Management in West Virginia. PHD Thesis. West Virginia University (Morgantown).
  • Meiners JM, Griswold TL, Carril OM (2019) Decades of native bee biodiversity surveys at Pinnacles National Park highlight the importance of monitoring natural areas over time. PLOS One 14(1): 1–23. https://doi.org/10.1371/journal.pone.0207566
  • Michener CD (1947) A revision of the American species of Hoplitis (Hymenoptera, Megachilidae). Bulletin of the American Museum of Natural History 89: 257–318.
  • Michener CD (2007) The Bees of the World, 2nd edition. Johns Hopkins University Press (Baltimore): 1–953.
  • Michener CD, Griswold TL (1994) The classification of old world Anthidiini (Hymenoptera, Megachilidae). The University of Kansas Science Bulletin 55(9): 299–327.
  • Michez D, Eardley C (2007) Monographic revision of the bee genus Melitta Kirby 1802 (Hymenoptera: Apoidea: Melittidae). Annales de la Société entomologique de France, New Series 43(4): 379–440. https://doi.org/10.1080/00379271.2007.10697535
  • Michez D, Patiny S (2005) World revision of the oil-collecting bee genus Macropis Panzer 1809 (Hymenoptera: Apoidea: Melittidae) with a description of a new species from Laos. Annales de la Société entomologique de France, New Series 41(1): 15–28. https://doi.org/10.1080/00379271.2005.10697439
  • Mikulas MM, Barringer LE (2018) First record of Bombus rufocinctus Cresson (Hymenoptera: Apidae: Bombini) in Pennsylvania. Insecta Mundi 0638: 1–2.
  • Milliron HE (1971) A monograph of the Western Hemisphere bumble bees (Hymenoptera: Apidae; Bombinae). I. Memoirs of the Entomological Society of Canada 103: 1–80. https://doi.org/10.4039/entm10382fv
  • Milliron HE (1973a) A monograph of the Western Hemisphere bumble bees (Hymenoptera: Apidae; Bombinae). II. Memoirs of the Entomological Society of Canada 105: 81–235. https://doi.org/10.4039/entm10589fv
  • Milliron HE (1973b) A monograph of the Western Hemisphere bumble bees (Hymenoptera: Apidae; Bombinae). III. Memoirs of the Entomological Society of Canada 105: 239–333. https://doi.org/10.4039/entm10591fv
  • Mitchell TB (1934) A revision of the genus Megachile in the Nearctic Region. Part I. Classification and descriptions of new species (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 59: 295–361.
  • Mitchell TB (1935a) A revision of the genus Megachile in the Nearctic Region Part II. Morphology of the male sternites and genital armature and the taxonomy of the subgenera Litomegachile, Neomegachile and Cressoniella (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61: 1–44.
  • Mitchell TB (1935b) A revision of the genus Megachile in the Nearctic Region Part III. Taxonomy of the subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61: 155–205.
  • Mitchell TB (1936a) A revision of the genus Megachile in the Nearctic Region Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62: 117–166.
  • Mitchell TB (1936b) A revision of the genus Megachile in the Nearctic Region Part V. Taxonomy of Subgenus Xeromegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 42: 323–387.
  • Mitchell TB (1937a) A revision of the genus Megachile in the Nearctic Region Part VI. Taxonomy of subgenera Argyropile, Leptorachis, Pseudocentron, Acentron, and Melanosarus (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63: 45–83.
  • Mitchell TB (1937b) A revision of the genus Megachile in the Nearctic Region Part VII. Taxonomy of the Subgenus Sayapis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63: 175–206.
  • Mitchell TB (1937c) A revision of the genus Megachile in the Nearctic Region Part VIII. Taxonomy of the Subgenus Chelostomoides, addenda and index (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 63: 381–426.
  • Mitchell TB (1960) Bees of the Eastern United States: Volume I. North Carolina Agricultural Experimental Station Technical Bulletin 141: 1–538.
  • Mitchell TB (1962) Bees of the Eastern United States: Volume II. North Carolina Agricultural Experimental Station Technical Bulletin 152: 1–557.
  • Mitchell TB (1980) A generic revision of the megachiline bees of the Western Hemisphere (Hymenoptera: Megachilidae). Contributions from the Department of Entomology, North Carolina State University (Raleigh): 1–95.
  • Montgomery GA, Dunn RR, Fox R, Jongejans E, Leather SR, Saunders ME, Shortall CR, Tingley MW, Wagner DL (2019) Is the insect apocalypse upon us? How to find out. Biological Conservation 108327. https://doi.org/10.1016/j.biocon.2019.108327
  • Müller A (2015) Palaearctic Chelostoma bees of the subgenus Gyrodromella (Megachilidae, Osmiini): biology, taxonomy and key to species. Zootaxa 3936(3): 408–420. https://doi.org/10.11646/zootaxa.3936.3.6
  • Normandin É, Vereecken NJ, Buddle CM, Fournier V (2017) Taxonomic and functional trait diversity of wild bees in different urban settings. PeerJ 5: p.e3051. https://doi.org/10.7717/peerj.3051
  • North American Native Bee Collaborative (2017) Bees of Maryland: A Field Guide. North American Native Bee Collaborative (Washington DC): 1–112.
  • Onuferko TM (2017) Cleptoparasitic Bees of the Genus Epeolus Latreille (Hymenoptera: Apidae) in Canada. Canadian Journal of Arthropod Identification 30: 1–62. https://doi.org/10.3752/cjai.2017.30
  • Ordway E (1966) Systematics of the bee genus Augochlorella (Hymenoptera, Halictidae) north of Mexico. The University of Kansas Science Bulletin 46: 509–624. https://doi.org/10.5962/bhl.part.20079
  • Owens BE, Allain L, Van Gorder EC, Bossart JL, Carlton CE (2018) The bees (Hymenoptera: Apoidea) of Louisiana: An updated, annotated checklist. Proceedings of the Entomological Society of Washington 120(2): 272–308. https://doi.org/10.4289/0013-8797.120.2.272
  • Packer L (1999) The distribution of Halictus ligatus Say and H. poeyi Lep. (Hymenoptera: Halictidae) in North America. University of Kansas Natural History Museum, Special Publication 24: 81–84.
  • Packer L, Ali E, Dumesh S, Walker K (2016) The identification of pollinators: where are we and where should we go? In: Gemmill-Herren B (Ed.) Pollination Services to Agriculture: Sustaining and enhancing a key ecosystem service. Routledge (New York), 75–91.
  • Packer L, Monckton SK, Onuferko TM, Ferrari RR (2018) Validating taxonomic identifications in entomological research. Insect Conservation and Diversity 11(1): 1–12. https://doi.org/10.1111/icad.12284
  • Parker FD (1978) An illustrated key to alfalfa leafcutter bees Eutricharaea. The Pan-Pacific Entomologist 54: 61–64.
  • Parker FD, Bohart GE (1979) Dolichostelis, a new genus of parasitic bees (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 52: 138–153.
  • Portman ZM, Burrows SJ, Griswold T, Arduser M, Irber AJ, Tonietto RK, Cariveau DP (2019) First Records of the Adventive Pseudoanthidium nanum (Mocsáry) (Hymenoptera: Megachilidae) in Illinois and Minnesota, with notes on its identification and taxonomy. The Great Lakes Entomologist 52(1): 12–20.
  • Potts SG, Biesmeijer JC, Kremen C, Neumann P, Schweiger O, Kunin WE (2010a) Global pollinator declines: trends, impacts and drivers. Trends in Ecology & Evolution 25(6): 345–353. https://doi.org/10.1016/j.tree.2010.01.007
  • Potts SG, Roberts SP, Dean R, Marris G, Brown MA, Jones R, Neumann P, Settele J (2010b) Declines of managed honey bees and beekeepers in Europe. Journal of Apicultural Research 49(1): 15–22. https://doi.org/10.3896/IBRA.1.49.1.02
  • R Core Team (2017) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. https://www.R-project.org/
  • Rehan SM, Richards MH (2008) Morphological and DNA sequence delineation of two problematic species of Ceratina (Hymenoptera: Apidae) from Eastern Canada. Journal of the Entomological Society of Ontario 139: 59–67.
  • Rehan SM, Sheffield CS (2011) Morphological and molecular delineation of a new species in the Ceratina dupla species-group (Hymenoptera: Apidae: Xylocopinae) of eastern North America. Zootaxa 2873: 35–50. https://doi.org/10.11646/zootaxa.2873.1.3
  • Ribble DW (1965) A Revision of the banded subgenera of Nomia in America (Hymenoptera, Halictidae). University of Kansas Publications 45: 277–357.
  • Ribble DW (1967) The monotypic North American Larandrena of Andrena (Hymenoptera: Apoidea). Bulletin of the University of Nebraska State Museum 6: 27–42.
  • Ribble DW (1968) Revisions of two subgenera of Andrena: Micrandrena Ashmead and Derandrena, new subgenus (Hymenoptera: Apoidea). Bulletin of the University of Nebraska State Museum 8: 237–394.
  • Ribble DW (1974) A revision of the bees of the genus Andrena of the Western Hemisphere subgenus Scaphandrena. Transactions of the American Entomological Society 100: 101–189.
  • Rightmyer MG, Griswold T, Arduser MS (2010) A review of the non-metallic Osmia (Melanosmia) found in North America, with additional notes on palearctic Melanosmia (Hymenoptera, Megachilidae). ZooKeys 60: 37–77. https://doi.org/10.3897/zookeys.60.484
  • Roberts RB (1972) Revision of the bee genus Agapostemon (Hymenoptera: Halictidae). The University of Kansas Science Bulletin 49: 437–590.
  • Rocha Filho LCD, Packer L (2016) Phylogeny of the cleptoparasitic Megachilini genera Coelioxys and Radoszkowskiana, with the description of six new subgenera in Coelioxys (Hymenoptera: Megachilidae). Zoological Journal of the Linnean Society 180(2): 345–413. https://doi.org/10.1111/zoj.12484
  • Rust RW (1974) The systematics and biology of the genus Osmia, subgenera Osmia, Chalcosmia, and Cephalosmia (Hymenoptera: Megachilidae). The Wasmann Journal of Biology 32: 1–93.
  • Sandhouse GA (1939) The North American bees of the genus Osmia (Hymenoptera: Apoidea). Memoirs of the Entomological Society of Washington 1: 1–167.
  • Sandhouse GA (1941) The American bees of the Subgenus Halictus. Entomologica Americana 21: 23–39.
  • Say T (1824) Order Hymenoptera. In: Keating WH (Ed.) Appendix to Narrative of an Expedition to the Source of St. Peter’s River, Lake Winnepeek, Lake of the Woods, &c. Performed in the Year 1823 by order of the Hon. JC Calhoun, Secretary of War, under the command of Major Stephen H Long. USTE, Volume 2. HC Carey and I Lea (Philadelphia), 310–356.
  • Schwarz HF (1926) North American Dianthidium, Anthidiellum, and Paranthidium. American Museum Novitates 226: 1–25.
  • Schwarz M, Gusenleitner F (2004) Beitrag zur Klärung und Kenntnis parasitärer Bienen der Gattungen Coelioxys and Nomada (Hymenoptera, Apidae). Linzer biologische Beiträge 36: 1413–1485.
  • Scott VL, Ascher JS, Griswold T, Nufio CR (2011) The Bees of Colorado (Hymenoptera: Apoidea: Anthophila). Natural History Inventory of Colorado: 1–100.
  • Sedivy C, Dorn S, Müller A (2013) Molecular phylogeny of the bee genus Hoplitis (Megachilidae: Osmiini) – how does nesting biology affect biogeography? Zoological Journal of the Linnean Society 167: 28–42. https://doi.org/10.1111/j.1096-3642.2012.00876.x
  • Sidhu CS (2013) Farmscape and landscape-level effects on Cucurbit pollinators on small farms in a diversified agroecosystem. PHD Thesis. The Pennsylvania State University (University Park).
  • Shugrue SE (2016) Pesticide use, habitat manipulation, and management changes as factors in pollinator sustainability in Pennsylvania apple orchards. MS Thesis. The Pennsylvania State University (University Park).
  • Sheffield C, Dumesh S, Cheryomina M (2011a) Hylaeus punctatus (Hymenoptera: Colletidae), a bee species new to Canada, with notes on other non-native species. Journal of the Entomological Society of Ontario 142: 29–43.
  • Sheffield CS, Hebert PD, Kevan PG, Packer L (2009) DNA barcoding a regional bee (Hymenoptera: Apoidea) fauna and its potential for ecological studies. Molecular Ecology Resources 9: 196–207. https://doi.org/10.1111/j.1755-0998.2009.02645.x
  • Sheffield CS, Ratti C, Packer L, Griswold T (2011b) Leafcutter and mason bees of the genus Megachile Latreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification 18: 1–107. https://doi.org/10.3752/cjai.2011.18
  • Sheffield CS, Heron J, Gibbs J, Onuferko TM, Oram R, Best L, deSilva N, Dumesh S, Pindar A, Rowe G (2017) Contribution of DNA barcoding to the study of the bees (Hymenoptera: Apoidea) of Canada: progress to date. The Canadian Entomologist 149(6): 736–754 https://doi.org/10.4039/tce.2017.49.
  • Shinn AF (1967) A revision of the bee genus Calliopsis and the biology and ecology of C. andreniformis (Hymenoptera, Andrenidae). The University of Kansas Science Bulletin 46: 753–936. https://doi.org/10.5962/bhl.part.20081
  • Snelling RR (1966) Studies on North American bees of the genus Hylaeus. 3. The Nearctic subgenera (Hymenoptera: Colletidae). Bulletin of the Southern California Academy of Sciences 65(3): 164–175.
  • Snelling RR (1968) Studies on North American bees of the genus Hylaeus. 4. The subgenera Cephalylaeus, Metziella and Hylaeana (Hymenoptera: Colletidae). Los Angeles County Museum Contributions in Science 144: 1–6.
  • Snelling RR (1970) Studies on North American bees of the genus Hylaeus. 5. The subgenera Hylaeus, s. str. and Paraprosopis (Hymenoptera: Colletidae). Los Angeles County Museum Contributions in Science 180: 1–59.
  • Snelling RR (1986) The taxonomic status of two North American Lithurge (Hymenoptera: Megachilidae). Bulletin of the Southern California Academy of Sciences 85(1): 29–34.
  • Soltani GG, Bénon D, Alvarez N, Praz CJ (2017) When different contact zones tell different stories: putative ring species in the Megachile concinna species complex (Hymenoptera: Megachilidae). Biological Journal of the Linnean Society 121(4): 815–832. https://doi.org/10.1093/biolinnean/blx023
  • Stephen WP (1954) A revision of the bee genus Colletes in America North of Mexico. The University of Kansas Science Bulletin 36: 149–527.
  • Svensson BG, Ebmer PAW, Sakagami SF (1977) Lasioglossum (Evylaeus) boreale, a new Halictinae (Hymenoptera: Apoidea) species found in northern Sweden and on Hokkaido, Japan, with notes on its biology. Insect Systematics & Evolution 8(3): 219–229. https://doi.org/10.1163/187631277X00297
  • Swenk MH (1915) Studies of North American bees. III. Families Nomadidae and Stelididae. University Studies of The University of Nebraska 15: 155–193.
  • Timberlake PH (1954) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea). Part I. University of California Publications in Entomology 9: 345–432.
  • Timberlake PH (1958) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea). Part III. University of California Publications in Entomology 14: 303–410.
  • Timberlake PH (1960) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea). Part IV. University of California Publications in Entomology 17: 1–156.
  • Timberlake PH (1967) New species of Pseudopanurgus from Arizona (Hymenoptera, Apoidea). American Museum Novitates 2298: 1–23.
  • Timberlake PH (1968) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea). Part VII. University of California Publications in Entomology 49: 1–196.
  • Timberlake PH (1969) A contribution to the systematics of North American species of Synhalonia (Hymenoptera, Apoidea). University of California Publications in Entomology 57: 1–76.
  • Timberlake PH (1973) Revision of the genus Pseudopanurgus of North America. University of California Publications in Entomology 72: i–vi + 1–58.
  • Timberlake PH (1975) The North American species of Heterosarus Robertson (Hymenoptera, Apoidea). University of California Publications in Entomology 77: 1–56.
  • Timberlake PH (1976) Revision of the North American bees of the genus Protandrena Cockerell (Hymenoptera: Apoidea). Transactions of the American Entomological Society 102: 133–227.
  • Turney S, Cameron ER, Cloutier CA, Buddle CM (2015) Non-repeatable science: assessing the frequency of voucher specimen deposition reveals that most arthropod research cannot be verified. PeerJ 3: e1168. https://doi.org/10.7717/peerj.1168
  • Williams PH, Thorp RW, Richardson LL, Colla SR (2014) Bumble bees of North America: An identification guide. Princeton University Press (Princeton): 1–208.
  • Williams PH, Cameron SA, Hines HM, Cederberg B, Rasmont P (2008) A simplified subgeneric classification of the bumblebees (genus Bombus). Apidologie 39: 46–74. https://doi.org/10.1051/apido:2007052
  • Winfree R, Williams NM, Gaines H, Ascher JS, Kremen C (2008) Wild bee pollinators provide the majority of crop visitation across land‐use gradients in New Jersey and Pennsylvania, USA. Journal of Applied Ecology 45(3): 793–802. https://doi.org/10.1111/j.1365-2664.2007.01418.x
  • Winfree R, Reilly JR, Bartomeus I, Cariveau DP, Williams NM, Gibbs J (2018) Species turnover promotes the importance of bee diversity for crop pollination at regional scales. Science, 359(6377): 791–793. https://doi.org/10.1126/science.aao2117
  • Wolf AT, Ascher JS (2009) Bees of Wisconsin (Hymenoptera: Apoidea: Anthophila). Great Lakes Entomologist 41(1–2): 129–168.
  • Wood TJ, Killewald MF, Graham KK, Gibbs J, Isaacs R (2019) Epeoloides pilosulus (Cresson) Rediscovered in Michigan, with Notes on the Distribution and Status of its Macropis hosts. The Great Lakes Entomologist 52(1): 1–5.
  • Zarrillo TA, Ascher JS, Gibbs J, Stoner KA (2016) New and noteworthy records of bees (Hymenoptera: Apoidea: Anthophila) for Connecticut. Journal of the Kansas Entomological Society 89(2): 138–158. https://doi.org/10.2317/0022-8567-89.2.138