Two unusual new species of Aulacus Jurine ( Hymenoptera , Aulacidae ) from South America

Aulacus flavus Smith, sp. n. from Brazil and Aulacus subflavus Smith, sp. n. from Brazil, French Guiana, and Guyana are described. These two species are separated from other Aulacus by the enlarged genae, flat mesoscutum, enlarged pronotum, and presence of small tubercles on the mesoprescutum, axillae, and mesoscutellum.


Introduction
Both genera of Aulacidae, Pristaulacus Kieffer and Aulacus Jurine, are widespread in the Neotropics.Twelve Neotropical species of Aulacus were listed by Smith (2001).Subsequently, 13 species have been added (Smith 2005a(Smith , 2005b(Smith , 2008;;Smith and Carvalho 2010).Here, I describe two species very different from other Aulacus species.

Materials and methods
Abbreviations: AEI, American Entomological Institute, Gainesville, FL; RBINS, Royal Belgian Institute of Natural Sciences, Bruxelles; CNC, Canadian National Collection of Insects, Ottawa, Ontario, Canada; MCZ, Museum of Comparative Zoology, Cambridge, MA; USNM, National Museum of Natural History, Smithsonian Institution, Washington DC.
Images were acquired through an EntoVision micro-imaging system.This system included a Leica M16 or Leica DRMB compound microscope with a JVC KY-75U 3-CCD digital video camera or a GT-Vision Lw11057C-SCI digital camera attached that fed image data to a notebook or desktop computer.The program Cartograph 6.6.0 was then used to merge an image series into a single in-focus image.

Results
The two species described below belong to Aulacus as currently defined (e.g., Smith 2001Smith , 2008;;Turrisi et al. 2009).They are distinguished from other Aulacus species in the first couplet in the key below.No other species of Aulacus share the flat mesoscutum, tubercles on the mesonotum, axillae, and scutellum, enlarged pronotum, and enlarged genae.The exact relationship with other species of Aulacus is unknown.Turrisi et al. (2009) considered the genus paraphyletic, and the phylogenetic classification remains unresolved.A study of world Aulacus on a much more comprehensive basis is needed to determine relationships of the two species described here.
Etymology.From Latin meaning yellow, with reference to the entirely yellow pronotum.
Remarks.There are slight variations in color, especially the amount of orange on the mesonotum and size of black marks on the metasoma.The entirely yellow pronotum seems to be constant in the specimens examined.Size is relatively stable, the length varying only by ±1.0 mm; proportions of the ovipositor and forewing remain the same regardless of length.Other specimens.BRAZIL: Sinop, M. Grosso, 12°31'S, 55°37'W, X.1974, M. Alvarenga (2 ♀, AEI); Vila Vera, 12°30'S, 50°30'W, October 1973, M. Alvarenga (2 ♀, AEI).

Aulacus subflavus
Distribution.Brazil: Mato Grosso; French Guiana; Guyana.Etymology.From the Latin partly yellow, referring to the usual half yellow and half black pronotum.
Remarks.The "other specimens" are structurally like this species but the mesosoma is entirely yellow orange and I prefer not to include them in the type series.The bicolored pronotum seems to be a helpful character, though several specimens have an entirely yellow pronotum.The side lobes of the mesonotum may be entirely black or partly orange.The length varies only by about ±0.7 mm; the proportions of the ovipositor and forewing remain the same regardless of size.