The splendidula species group includes Palaearctic species recognizable by the last metasomal tergum which is coloured blue or green, usually contrasting with metasomal terga I–II which are red. However, exceptions to this colouration pattern are five Central Asian species with terga I–II blue or blue with green to light blue stripes (Chrysis centralis Semenov-Tian-Shanskij, 1967; C. circassica Mocsáry, 1893; C. hyacinthus Semenov-Tian-Shanskij, 1967; C. kokandica Radoszkowsky, 1877; C. serpentula Semenov-Tian-Shanskij, 1967) and a Japanese one (C. nohirai Tsuneki, 1952).

Members of the splendidula species group can be recognised by the combination of the following characters: transverse frontal carina distinct and raised; apical margin of metasomal tergum III with four sharp teeth, and black spots on sternum II elongate, connected to lateroterga and widely separated in the middle (Fig. 1F).

Figure 1. 

Chrysis arkadyi sp. nov., female, holotype A habitus, dorsal view B head, frontal view C habitus, lateral view D metasoma, dorso-lateral view E metasoma, posterior view F metasoma, ventral view. Scale bars: 1.0 mm.

Face with distinct and raised transverse frontal carina, M-like or biconvex, recurved below; scapal basin medially polished to finely wrinkled; malar spaces usually 1.0–1.5 × MOD; second flagellomere usually slightly shortened; carina on metasomal tergum II indistinct or as an impunctate line, rarely raised and sharp; tergum III with distinct row of small, round to slightly elongate pits; apical margin of tergum III with four sharp, triangular teeth; black spots on sternum II widely separated and elongate, adjacent to lateral margin.

Vespidae: Eumeninae (Martynova and Fateryga 2015).

Kimsey and Bohart (1991) subdivided the splendidula species group into two subgroups: the splendidula s.str. subgroup and the splendidula-senegalensis subgroup. We here consider these two groups as separated because of the different shape of female internal terga that form the telescopic ovipositor (Rosa et al., in preparation).

Chrysis arkadyi sp. nov. is the only known member of the splendidula group from India and Pakistan so far. Conversely, four species of the senegalensis group are known for India (Rosa et al. 2021), namely: Chrysis disparilis Cameron, 1897, C. hecate Mocsáry, 1889, C. ionophris Mocsáry, 1893, and C. sikkimensis Mocsáry, 1912.

Tarbinsky (2002) established the serpentula species group, based on misidentified specimens of Chrysis serpentula Semenov-Tian-Shanskij, 1967. After type examination (Rosa et al. 2017, fig. 122) we include this species in the splendidula species group and we here synonymize the serpentula species group with the splendidula species group.

Holotype , ♀, India: Uttaranchal: Haldwani, Kathgodam, ca 800 m, 21.–22.vii.2003, Z. Kejval & M. Trýzna leg. (MSNM). Paratypes: Pakistan: 1♂, Khyber Pakhtunkhwa: NE of Mansehra, ca 1200 m, Barhadi env., 34°24'00"N, 73°19'48"E, 20.v.2019, D. Baiocchi leg. (DBC); 2♀♀, NE of Mansehra, ca 1200 m, Barhadi env., 34°24'00"N, 73°19'48"E, 20.v.2019, M. Kafka leg. (MHC, PRC).

Chrysis arkadyi sp. nov. is recognised by the following characters: body blue with light blue and greenish reflections (Fig. 1), with black median area of mesoscutum, and with wide green bands laterally and posteriorly on terga I–II; metapostnotum T-like, reduced to a small median area, with punctures smaller than those on metascutellum; metasoma with terga I–II extremely elongated compared to other species in the splendidula species group; tergum III with polished and elongate post pit row area; black spots on sternum II elongate and sub–ovoid. This new species can be distinguished from other blue coloured Central Asian species of the same species group by reduced metapostnotum, elongated metasomal terga and elongate post pit row area. This species is more closely related to Chrysis nohirai Tsuneki, for the elongate shape of metasomal tergum II (type examination based on pictures taken by T. Mita). However, C. arkadyi sp. nov. is easily distinguished by: transverse frontal carina M-shaped; dense body punctation, in particular on mesonotum, mesopleuron and second tergum; structure of metasomal tergum I elongate, 0.6 × as long as length of tergum II and structure of tergum III with post pit row distinctly elongate (1.5 MOD) (vs. transverse frontal carina medially straight and laterally downcurved; body sparsely punctate, with wide impunctate interspaces on lateral areas of mesoscutum, mesopleuron and second tergum, and unmodified structure of tergum I, 0.4 × as long as length of tergum II and of tergum III, with post pit row not distinctly elongate (1.0 MOD) in C. nohirai).

Holotype: Female. Body length 6.6 mm. Head. Scapal basin medially striate and laterally micropunctate (Fig. 1B). Transverse frontal carina broadly M-shaped. Anterior margin of clypeus medially not emarginate, with thickened brownish rim. Face with large and coarse punctures between transverse frontal carina and scapal basin; vertex with smaller punctures. Genal carina sharp, present from temple posteriorly to mandible. Relative length of P:F1:F2:F3 = 1.0:1.3:0.9:0.8; OOL = 2.0 × MOD; POL = 2.3 × MOD; MS = 1.3 × MOD; subantennal space 1.0 × MOD. Mesosoma. Pronotum slightly shorter than mesoscutellum (Fig. 1C); antero-median pronotal line deep, broad and reaching half of pronotum length; punctation double, coarse along anterior and lateral margins, with smaller punctures on antero-median pronotal line and along posterior margin. Median area of mesoscutum in posterior half with larger punctures and broader polished intervals; lateral areas of mesoscutum with irregularly sized punctures and corrugated interspaces; parapsidal furrow distinctly engraved; notauli as line of sub-square pits, decreasing towards anterior margin of mesoscutum. Mesoscutellum with larger punctures and broad, polished interspaces, locally with tiny punctures; laterally with smaller, dense punctures along metanotal trough. Metanotum slightly convex, with large, polygonal and uneven punctures; anterior margin of metanotum with large impunctate and depressed median area. Mesopleuron almost without trace of episternal sulcus, with large punctures and densely, minutely punctate intervals; scrobal sulcus as deep, polished line (Fig. 1A); metapostnotum reduced, triangular, T-shaped, with small punctures and with two largely expanded lateral areas, with raised transverse carinae; posterior propodeal projections laterally expanded and downward directed, with basal margin slightly concave. Metasoma. Metasoma densely punctate; puncture diameter about 1/2 to 1/3 of largest punctures on mesoscutellum; metasomal terga elongate (Fig. 1C–F), tergum I 0.6 × as long as length of tergum II; tergum III slightly longer than tergum I; tergum II with weak median ridge; pit row of tergum III deep, with elongated, large pits; post pit row distinctly elongate (1.5 MOD); apex of T3 with four short, triangular teeth; intervals between median and lateral teeth almost equal; black spots on sternum II sub-ovoid, narrow and connected to lateral margins, widely separated medially (Fig. 1F). Colouration. Body blue to deep blue, almost black on ocellar area, median area of mesoscutum and basally on metasomal tergum II; green on scape, pedicel, first flagellomere, postero-laterally on terga I–II, on tergum III pre pit row, and on sternites (Fig. 1C–F); other flagellomeres black; tegula light blue; post-tegula bright metallic blue; forewing slightly infuscate, with darkened radial cell.

Male. Similar to female (Fig. 2A–D), with deep blue body colour and fewer greenish hints. Paratype body length 6.2 mm. The main dimorphic difference is observed in the metasomal tergum III for shorter post pit area and apical margin with median teeth shorter and closer to each other, compared to apical teeth of female.

Figure 2. 

Chrysis arkadyi sp. nov., male, paratype (A–D, F), female, holotype (E) A genital capsule B habitus, dorsal view C head, frontal view D metasoma, dorso-lateral view E, F internalised segments. Scale bars: 1.0 mm.

The Pakistani specimens of Chrysis arkadyi sp. nov. described herein were captured by means of yellow pan traps positioned along one of the roads through the forest zone of the Manshera district, about one kilometer NE of the village of Barhadi. The forest is mainly composed of Pinus roxburghii Sargent (Fig. 4).

The specific epithet arkadyi is a patronym honouring Prof. Dr. Arkady Stepanovich Lelej on the occasion of his 75^th birthday and in recognition of his numerous contributions to the study of the Hymenoptera and of the Russian Chrysididae.

The succincta species group includes more than a hundred species distributed worldwide, with a large majority known in the Palaearctic region, and subdivided into succincta s.str. subgroup and leachii subgroup (or leachii group according to Linsenmaier 1959). Usually, Palaearctic species are easily recognised by their slender habitus and by their peculiar colouration, with the body largely red coloured. The most diagnostic feature is anyhow the prominent brow, often ridge-like, and the transverse frontal carina which is usually only partially developed; females scapal basin is always polished medially in the succincta s.str. subgroup, whereas it is finely striated in the leachii subgroup, while in males it is finely punctate in both subgroups. The apical margin of tergum III is highly variable, bearing from none to four teeth or two median teeth almost fused together and projecting medially.

Crabronidae (Pauli et al. 2019).

Linsenmaier (1997) established the autocrata species group, based on Chrysis autocrata Nurse, 1903. After type examination of the latter, we propose the new synonymy Chrysis variana du Buysson, 1901 = Chrysis autocrata Nurse, 1903, syn. nov. Chrysis variana (see pictures of the type in Rosa et al. 2020) is a widespread Central Asian species of the succincta group (known from Kazakhstan, Kyrgyzstan, Tadjikistan, Turkmenistan and Pakistan), and apparently unknown to Linsenmaier, as it is not listed in his papers and was not found in his collection. Consequently, we synonymize the autocrata species group with the succincta species group, because it is not sufficiently supported by morphological diagnostic characters. During the examination of the Palaearctic types of cuckoo wasps, the first author also observed that the holotype of Chrysis ewridica Tarbinsky, 2001 (described from Kyrgyzstan, Jalal-Abad) is a female of Chrysis variana and therefore we here propose also the new synonymy Chrysis variana du Buysson, 1901 = Chrysis ewridica Tarbinsky, 2001, syn. nov.

Pakistan: 1♀, Khyber Pakhtunkhwa: NE of Mansehra, ca 1200 m, Barhadi env., 34°24'00"N, 73°19'48"E, 20.v.2019, M. Kafka leg. (MHC).

Pakistan (Khyber Pakhtunkhwa, first record), India (Maharashtra), Nepal (Chhumchaur, 29°21'30"N, 82°23'46"E, 16.vi.1997 (PRC)) (new record).

Figure 3. 

Chrysis speculata du Buysson, female, from Pakistan A habitus, dorsal view B habitus, lateral view C head, frontal view D metasoma, dorso-lateral view E metasoma, ventral view. Scale bars: 1.0 mm.

Figure 4. 

Pakistan, type locality of Chrysis arkadyi sp. nov., forest composed of Pinus roxburghii.