4. Hind basitarsus simple ... 5

– Hind basitarsus bearing processes, spines, leaf-like or long setae ... 7

5. Fore tarsus having segments regularly decreasing in length; mid femur with 2-3 long ventral setae; 4.0-4.5... miki Strobl

– Fore tarsus with shortened 2^nd-4^th segments; each segment hardly longer than wide ... 6

6. Fore femur with 3-4 ventral setae at base; mid femur with ventral row of 3-5 setae in basal half; 4^th segment of fore tarsus bearing one dorsal seta; 2.5-3.0 ... pumilus(Meigen)

– Fore femur with ventral hairs only, without setae; mid femur with ventral row of at least 6 setae in basal half; 4^th segment of fore tarsus without dorsal seta; 4.0-4.5 ... metathesis(Loew)

7. Hind tibia plumose dorsoventrally; hind basitarsus with 1 curved seta in middle and 2 short setae at apex; 3.0; [Norway]... pennatus Ringdahl

– Hind tibia without long setae ... 8

8. Some segments of mid tarsus widened ... 9

–Mid tarsus simple ... 10

9. 2^nd-4^th segments of mid tarsus strongly widened and compressed laterally, black; hind tarsus black; legs including coxae yellow; hind tibia at apex thickened, black; hind tarsus black; hind basitarsus with long curved ventral seta; postpedicel 3 times longer than high at base; 3.0. Figs. 193 (1-2). ... tarsatus(Fallén)

– 4^th and 5^th segments of mid tarsus widened; mid and hind coxae grey-black; hind tibia yellow, not thickened at apex; hind basitarsus with long pointed ventral process; postpedicel 1.5 times longer than high at base; 2.5-2.75. Fig. 193 (3)... monilis (Haliday)

10. Hind basitarsus with long simple ventral setae ... 11

– Hind basitarsus with hook-like curved setae, with leaf-like appendix or with process ... 12

11. Fore femur bearing long ventral seta at base; 1^st and 2^nd segments of hind tarsus each with 1 ventral seta; 2.0... filiger Verrall

– Fore femur without long ventral seta; hind basitarsus with 2 strong ventral setae of equal length; 3.0 ... punctatus(Zetterstedt)

12. Hind basitarsus with 1 leaf-like pedunculate ventral appendix; 2.5-3.0... subinermis (Loew)

– Hind basitarsus with unguiculate ventral spines or with process ... 13

13. Hind basitarsus with basoventral tubercle bearing bunch of modified setae, at most slightly shorter than 2^nd segment; 3.0-3.25... fuscipes(von Roser)

– Hind basitarsus with only two bare ventral hooks in basal half, without long setae or process ... 14

14. Postpedicel 3-3.5 times longer than high, nearly 2 times longer than stylus; mid femur without strong ventral setae; hind basitarsus with strong ventral hooks; 3.0-3.75. Fig. 193 (4)... pallipes (Fabricius)

– Postpedicel 1.5-2 times longer than high, shorter than stylus; mid femur with row of ventral setae; hind basitarsus with weak spiniform ventral setae; 3.25-4.0. Fig. 193 (5)... denticulatus(Zetterstedt)

15. Face having 2 setae; coxae yellow; mid coxa darkened; abdomen partly yellow; fore tibia with 1 anteroventral seta ... miki Strobl

– Face without setae ... 16

16. Coxae yellow; sometimes mid coxa barely darkened ... 17

– At least mid and hind coxae dark ... 19

17. Abdomen yellow; metaepimeron yellow; acrostichal setae uniseriate ... punctatus(Zetterstedt)

– Abdomen dark; rarely segments II and III with yellow spots ... 18 

18. Acrostichal setae biseriate; mid tarsus darkened; abdomen with yellow spots ... fuscipes(von Roser)

– Acrostichals uniseriate; mid tarsus yellow ... tarsatus(Fallén)

19. Fore coxa dark at least laterally; frons green or bronze-green ... 20

– Fore coxa yellow at least in apical half; frons usually with blue tinge (except for denticulatusZett.) ... 21

20. Fore coxa with mostly black hairs and setae at apex; frons mat; fore tibia without serration; mid coxa with 1 black seta; lower calypter with black cilia ... filiger Verrall

– Fore coxa with white hairs, sometimes with 1-2 black setae at apex; frons brownish pollinose; fore tibia with anterodorsal serration; mid coxa without strong setae ... denticulatus(Zetterstedt)

21. Abdomen partly yellow laterally; acrostichals uniseriate; hind basitarsus light at base ... pallipes (Fabricius)

– Abdomen usually dark ... 22

22. Fore femur dark at base; fore coxa yellow at apex only; hind trochanter dark ... 23

– Fore femur yellow; fore coxa dark at base; hind trochanter yellow ... 24

23. Frons mat, bronze-green ... denticulatus (Zetterstedt)

– Frons shining blue ... pumilus(Meigen)

24. 1^st-3^rd segments of tarsi yellow, at most dark at apex; fore tibia without posterodorsal seta ... monilis (Haliday)

– Tarsi dark from tip of basitarsi ... 25

25. Antennal scape haired above; fore coxa with black apical setae ... metathesis(Loew)

– Scape bare above; fore coxa with white hairs only ... 26

26. Postpedicel longer than high at base, drawn-out at apex ... pallipes (Fabricius)

– Postpedicel not longer than high, trapezoid, with almost straight dorsal margin ... subinermis (Loew)