Syrphoctonus borealis

Syrphoctonus borealis (Holmgren 1858, Bassus)

Syrphoctonus novitus Dasch 1964a

Diagnosis. Fore wing length 4.0– 4.5 mm. Antenna in females with 20, in males with 20–21 flagellomeres, with tyloids on flagellomeres 6 to 15. Epicnemial carina only weakly interrupted behind fore coxa. Mesoscutum smooth and shining and distinctly punctate. Propodeum with pleural and lateral longitudinal carinae developed, the latter rather strong, sculpture rugose, especially on petiolar area. Female metasoma gradually tapered to apex, a little elongate, first tergite 1.1 times longer than wide in females, 1.1–1.2 in males; spiracle of third tergite clearly below lateral fold.

Colouration of females. Antenna dark brown. Head and mesosoma black, orange or brown on clypeus, sides and mandibles dark, dark orange on tegula and upper mesepimeron. Legs orange, all coxae and trochanters black; femora orange, not marked with black; hind tibia orange with a dark apex, tarsus dark. Metasoma black with yellow marks on posterior corners of tergite 3.

Colouration of males. As in females but with antennae ligher below, yellow on scape and pedicel below, central face patch and along inner orbits, clypeus, mouthparts, hind corner of pronotum, tegula, subtegular ridge, large shoulder mark with its inner corners a little extended onto mesoscutum. Fore and mid coxae with yellow apices. Metasoma black with yellow marks on posterior corners of tergites 3 or 4 to 5.

Material examined. Lectotype of Bassus borealis Holmgren: Sweden, Lapland, leg. Boheman. 1♂, at NRM.

Additional material. Sweden, Lapland, Abisko, 17.IX.1918, 1♂; Lapland, leg. Boheman, 1♂; Lapland, VII.1922, 1 ♀; Lapland, 27.VII.1908, 1♂; all at NRM.

Distribution. Western Palaearctic and Nearctic.

Notes. This species was placed by Dasch (1964a) in the elegans species group of Homotropus but clearly belongs in Syrphoctonus.