Syrphophilus tricinctorius (Thunberg 1824, Ichneumon)

Bassus cinctus Gravenhorst 1829

Bassus lateralis Gravenhorst 1829

Bassus albicinctus Desvignes 1862

Bassus scapulatus Provancher 1883

Homocidus takaozanus Uchida 1930

Syrphophilus niveus Dasch 1964a

Diagnosis. Fore wing length 4.6–5.9 mm. Antenna of both sexes with 19–21 flagellomeres. Mesoscutum smooth and shining between weak punctures. Mesopleuron smooth and shining between weak punctures which are more than their diameter apart. Sternaulus weakly to strongly impressed. Propodeum with a full set of strong carinae enclosing basal, lateral and petiolar areas, the areas with rugose to coriaceous sculpture. First tergite with median dorsal carinae strongly developed at least on basal half. Second and third tergites with punctures indistinct against the rugulose or coriaceous background.

Colouration of females. Antenna black or brown. Head and mesosoma black, face with yellow along inner orbits, yellow on clypeus, mouthparts, hind corner of pronotum, tegula, usually subtegular ridge, small to large shoulder mark, and often upper mesepimeron; scutellum partly yellow, at least with yellow apex. Legs orange, coxae black, fore and mid coxae with yellow apices, trochanters yellow; femora orange; hind tibia orange with apex dark, hind tarsus dark. Metasoma black, often with small spots on posterolateral corners of tergites 2 to 3 or 4.

Colouration of males. As in females but with yellow ventrally on scape, pedicel and sometimes basal flagellomeres, face entirely yellow, yellow on propleuron, epicnemium, front part of mesosternum, and often a stripe or dot on lower mesopleuron. Fore and mid coxae entirely yellow, hind coxa black with a yellow apex. Metasoma black, usually with yellow apical bands on tergites 1 or 2 to 4 or 5.

Material examined. Holotype of Ichneumon tricinctorius Thunberg: Sweden, Uppsala . 1♂, at UU.

Finland (3), Germany (2), Hungary (10), Norway (4), Russia (5), Sweden (60), Switzerland (>100), United Kingdom (30).

Distribution. Holarctic and Oriental.

Figures. Metasoma (Fig. 14A), sternaulus (Fig. 25B), habitus (Fig. 33 F).