Sussaba dorsalis

Sussaba dorsalis (Holmgren 1858, Bassus)

Bassus maculatus Desvignes 1862

Diagnosis. Fore wing length 3.5–4.1 mm. Antenna in females with 18–21 flagellomeres, with ventral area of median to apical flagellomeres with conspicuous areas bearing a short velvety pile and lacking multiporous plate sensilla; in males with 21–22 flagellomeres, with two-coloured tyloids on flagellomeres 5/6 to 10. Face mainly smooth and shining, impunctate, with some irregular sculpture centrally and along inner orbits. Mesoscutum smooth and shining, between somewhat irregular punctures and sculpture. Mesopleuron entirely smooth and shining, impunctate. Hind coxa with outer hind surface mostly smooth and shining, without any sculpture apart from around seta roots. Propodeum with a full set of carinae enclosing basal, lateral and petiolar areas, the areas with rugose to coriaceous sculpture. Metasoma strongly compressed posterior to second segment, knife-like, first tergite 1.2–1.6 times longer than wide in females and 1.4–1.7 in males.

Colouration of females. Antenna dark brown, paler below. Head and mesosoma black, face usually with a yellow central face patch, clypeus black, yellow on mouthparts, hind corner of pronotum, tegula, subtegular ridge, sometimes a small shoulder mark, upper mesepimeron; scutellum black. Legs orange, fore and mid coxae yellow, sometimes with black at extreme base, hind coxa usually entirely black or with a yellow apex, trochanters yellow, hind trochanter usually marked with black; femora orange, marked with black below at extreme base; hind tibia and tarsus orange to brown. Metasoma variously marked with orange, usually at least on hind margin of tergite 2 and on tergites 3 and 4, there often with a dark, diamond-shaped mark medially.

Colouration of males. As in females but with yellow ventrally on scape and pedicel, entire face, epicnemium, and sometimes a large shoulder mark. Hind trochanter often entirely yellow. Metasoma often as in female, the pattern of orange tergites 3 and 4 with median diamond-shaped marks often even more pronounced but sometimes with yellow spots basally on tergite 3.

Material examined. Lectotype of Bassus dorsalis Holmgren: Sweden, Lapland, leg. Boheman. 1♀, at NRM (designated by Townes et al. 1965) (a different female with the same data marked as a lectotype by K. Horstmann is also present in the collection; Townes’ designation has priority).

Austria (1), Finland (5), Germany (2), Hungary (2), Netherlands (3), Norway (1), Sweden (80), Switzerland (20).

Distribution. Holarctic.

Figures. Metasoma ♀ (Fig. 23 C).

Notes. While females of this species can be identified very easily by the strongly compressed metasoma, some males might be confounded with male S. pulchella. While colouration and length of the metasoma provide good evidence in most specimens, some males are very difficult to place.

The subspecies Sussaba cultriformis (Ashmead 1890, Trematopygus), a former subspecies of S. dorsalis, is here-in elevated to species rank. Material of this species examined: Holotype, 1♀, USA, Nebraska, leg. L. Brunnel, at USNM. Additional material. USA, Alaska, Fairbanks, North Star Borough, leg. D.Fieldling, N.Schiff, 20.– 24.6.2006. 3♀, at NMBE.