– Lateral scutellars at least 1/3 as long as median setae ... 6

3. Face distinctly bicolorate, with epistome brown or greyish pollinose and clypeus more or less shining ... 4

– Face entirely dusted, monochrome ... 5

4. Femora mostly black; postocular and proepisternal bristles whitish; 1.4-1.7. Fig. 125 ... micacea Loew

– Femora mostly yellow; proepisternal bristles black, postoculars partly black; 2.0-2,5 ... annulitarsa von Roser

5. Legs including front coxa mainly yellow; male cercus without strong apical setae; 1.6-2.5. Fig. 111 ... plumbella Meigen

– Legs black, with yellow knees; male cercus with a strong spiniform apical seta; 1.6-2.1.Fig. 117 ... senicula Kowarz

6. Dorsocentral bristles not gradually decreasing anteriad; either 5 strong setae with 1^st one often reduced or lost and rest setae equally long, or 4 setae with 2^nd one shorter than rest, or 3 dorsocentrals equally long ... 7

– Dorsocentral bristles gradually decreasing from long setae posteriad into short setae anteriad, having usually no long and strong presutural bristles in their rows ... 11

7. Only 1 supraalar bristle; distal part of CuA₁ at least 2 times longer than m-cu; legs mainly brown with tibiae and tarsal bases often yellow; 2.0-2.3. Fig. 100... betulae Ringdahl

– 2 strong supraalar bristles; legs including tibiae mainly black; distal part of CuA₁ only slightly longer or shorter than m-cu ... 8

8. 4 strong dorsocentrals with 2^nd bristle distinctly shorter than rest; distal part of CuA₁ slightly longer than m-cu; 2.0-2.7. Fig. 122 ... truncorum Meigen

– 4 strong dorsocentrals equally long or practically so, or when 5 bristles the front one is shorter than rest; distal part of CuA₁ distinctly shorter than m-cu; 2.5-4.0 ... 9

9. Mesonotum uniformly dusted greyish or whitish; otherwise similar to M. petrophila; 3.2-3.4. Fig. 91 ... tenuicauda Loew

– Mesonotum longitudinally striped brownish ... 10

10. Face including clypeus entirely covered with greyish dusting; arista subapical; anteroventral bristles at tip of hind femur longish; m-cu perpendicular to longitudinal wing axis; 2.7-4.0.Fig. 92, 130 ... jacula (Fallιn)

– Clypeus at least partly shining metallic; arista apical; anteroventral bristles at tip of hind femur short; m-cu distinctly oblique; 2.7-3.4. Fig. 115 ... petrophila Kowarz

11. Scape (often also pedicel) yellow; usually more than 6 strong dorsocentrals gradually decreasing in size anteriad; male cercus usually without apical bladelike setae ... 12

– Antenna entirely black, or in immature specimens slightly reddish; usually no more than 5 strong dorsocentrals; anteriormost strong bristles (usually at suture or just presuturally) at least 3 times size of anterior short setulae; cercus usually with dorsoapical flattened, bladelike setae ... 22

12. Apical part of M₁₊₂ vein practically straight ... 13

– Apical part of M₁₊₂ vein distinctly curved ... 15

13. Front femur with long anteroventral setae in apical ½ and long posteroventral setae at base; mid femur with long anteroventral setae; arista 1.5 times longer than antenna; 2.3-2.9. Fig. 127 ... fasciata Frey

– Front femur with short ventral cilia ... 14

14. Mid femur with short anteroventral setae; arista no more than 1.5 times longer than antenna; halter yellow; 2.2-3.2. Fig. 120 ... striata Parent

– Mid femur with anteroventral setae mostly longer than diameter of femur; arista 2-3 times longer than antenna; halter brown; 2.7-3.0. Fig. 118 ... setiventris Thuneberg

15. Halter dark; hypandrium expanded subapically, with drawn-out apex and sigmatoid subapical indentations; aedeagus sharply tridentate ... 16

– Halter yellow; aedeagus usually without lateral dents; hypandrium various (males only) ... 17

16. Postocular cilia brown; surstylus distinctly trilobate at apex; 2.2-2.6. Fig. 126 ... zinovjevi Negrobov

– Postocular cilia whitish; surstylus bilobate; 2.9-3.5. Fig. 119 ... signaticornis Loew

17. Lower postocular cilia brown black, sometimes with admixture of light cilia ... 18

– Lower postocular cilia yellow ... 19

18. Hind tibia with 3 to 5 strong subapical dorsal bristles (see below) ... obscura (Zetterstedt)

– Hind tibia without distinctive dorsal bristles at tip; hypandrium symmetrical, expanded subapically (ventral view); 3.0-4.0.Fig. 102 ... dichrocera Kowarz

19. Hind tibia with a short strong curved spine anteriorly at tip; the spine consisting of 2-3 coalesced setae; hypandrium simple, symmetrical, expanded apically (ventral view); 3.2-3.6.Fig. 109 ... nitida (Macquart)

– Hind tibia without curved spine at tip ... 20

20. Hind tibia with 3 to 5 strong subapical dorsal bristles; hypandrium with 2 long subbasal lateral hooked lobes of unequal length; surstyli strongly swollen basoventrally; 3.5-4.9.Fig. 110 ... obscura (Zetterstedt)

– Hind tibia without distinctive bristles above near tip, at most a very small dorsal preapical bristle ... 21

21. Hypandrium with right basal expansion and left subapical internal projection (ventral view); 2.5-3.0.Fig. 116 ... pinicola Kowarz

– Hypandrium symmetrical, slightly swollen apicad, with 2 pointed midlateral lobes; 3.2-4.0. Fig. 99 ... adjaniae Gosseries

22. Large species: 3.7-4.6 mm; clypeus brilliant shining metallic green without lateral pruinosity; m-cu 1.5-2 times longer than distal part of CuA₁; tibiae yellow to darkish brown; acrostichals very small and extremely numerous; 3.7-4.5. Fig. 128... diadema (Linnaeus)

– Smaller species, less than 3.5 mm; clypeus usually dull metallic colour, usually covered with pruinosity laterally, m-cu only slightly longer or shorter than distal part of CuA₁ ... 23

23. At least front and mid tibiae yellow or pale brownish; distal part of CuA₁ at least 2 times longer than m-cu ... 24

– Legs including tibiae blackish or dark brown, at most knees narrowly yellow ... 26

24. CuA₁ simple at base, not obviously thicker than M₁₊₂; coxal and femoral hairs and bristles more pale brownish; 1.8-2.2. Fig. 113 ... pallipes (Zetterstedt)

– Males with a strong thickening at base of CuA₁; the thickening tapered and about ½ as long as discal cell; females with CuA₁ at base markedly thicker than M₁₊₂ at base; coxal and femoral hairs and bristles conspicuously whitish; 2.0-2.5 ... 25

25. Male hypandrium strongly swollen in basal 1/2, with lateral denticles; 1.7-2.0.Fig. 105... inspissata Collin

– Male hypandrium simple; 2.0-2.5.Fig. 103... excellens Frey

26. Face polished, entirely brilliant, rarely slightly dusted laterally on clypeus or finely striated under antennae, epandrial lobes fused basally ... 27

– At least epistome mostly dusted or dull metallic, dark coloured and weakly shining, often punctate or granular, sometimes strongly striated ... 29

27. Halter dark, blackish or brown; apical section of M₁₊₂ slightly but distinctly curved; face shining deep blue; 2.4-3.5. Fig. 94 ... ambigua (Zetterstedt)

– Halter yellow, apical section of M₁₊₂ strongly curved; face shining green ... 28

28. 2 strong and 2 fine whitish proepistrernal setae; cercus with lobe and bladelike seta apically; hypandrium simple; 2.6-3.0. Fig. 114 ... parenti Stackelberg

– 4 strong black proepisternal setae; male cercus simple, with simple setae; hypandrium with tooth-like lateral lobes; 3.0-3.5. Figs. 90, 106 ... melancholica Lundbeck

29. Epandrial lobes fused, forming long process bearing 2 setae at its apex; hypandrium narrow, gradually tapering; distal part of CuA₁ approximately as long as m-cu ... 30

– Epandrial lobes greatly reduced, more or less separated; hypandrium subrectangular, usually swollen subapically (ventral view); distal part of CuA₁ usually more than 1.5 times longer than m-cu (except for M. cuspidata) ... 32

30. Halter pale yellow, lower postoculars white, 1 or 2 epandrial setae usually plumose, 2.0-2.7. Fig. 93, 124 ... veles Loew

– Halter dark, lower postoculars usually dark ... 31

31. 2-3 brown proepisternal setae; lower postoculars yellow to brownish; 1 or 2 epandrial setae usually plumose; 1.8-2.5.Fig. 107 ... infumata Loew

– 3-6 strong black proepisternal setae; lower postoculars black; epandrial setae simple; 3.0-3.5. Fig. 123 ... vagans Becker

32. Halter blackish-brown ... 33

– Halter yellow, sometimes brownish-yellow in places ... 34

33. Lower postocular and proepisternal setae black; distal part of CuA₁ 1.9 times longer than m-cu; 1.9-2.3.Fig. 121 ... tristis (Zetterstedt)

– Lower postocular and proepisternal setae yellow; distal part of CuA₁ 1.3 times longer than m-cu; 2.1-2.3. Fig. 129 ... cuspidata Collin

34. Lower postoculars black brown ... 35

– Lower postoculars yellow ... 37

35. Distal part of CuA₁ 1.5 times longer than m-cu; 2.5-2.8.Fig. 112 ... pseudoapicalis Thuneberg

– Distal part of CuA₁ at least 2 times longer than m-cu ... 36

36. 2 proepisternal setae; 2.4-2.8.Fig. 95 ... abstrusa Thuneberg

– 3-4 proepisternal setae; 2.2-2.6.Fig. 96 ... acanthura Negrobov & Thuneberg

37. Epistome matt, densely grey pollinose; hypandrium widest in middle (ventral view); 2.4-2.5 ... glauca Loew

– Epistome shining at least below middle ... 38

38. Tibiae and basitarsi yellow-brown; epandrium elongated, 3 times longer than high, with elongated appendages; dorsal lobe of surstylus higher than ventral lobe (lateral view); cercus with 2 long and thin apical and subapical flattened setae; 2.6.Fig. 101... gracilicauda Parent

– Legs black with yellow knees, at most tibiae brown; epandrium not more than 2.5 times longer than high; dorsal lobe of surstylus thin; cercus with only apical flattened seta long ... 39

39. Mid femur with short anteroventral bristles, sometimes longer ones at tip; hypandrium thin to apex (ventral view); 2.1-2.5.Fig. 97 ... apicalis (Zetterstedt)

– Mid femur with rather long anteroventral bristles, the longest more than half as long as femur deep; hypandrium widened in distal 1/3 or 1/2 ... 40

40. Abdomen pale-haired; hypandrium with rhomboid widening in distal 1/3; 2.1-2.7. Fig. 131 ... jugalis Collin

– Abdomen dark-haired; hypandrium with ovoid widening in distal 1/3 or 1/2... 41

41. Hind femur with short and inconspicuous anteroventral bristles; hypandrium widened in distal 1/2; 2.2-2.7. Fig. 104 ... impigra Collin

– Hind femur with long anteroventral bristles at least at tip; hypandrium widened in distal 1/3; 2.0-2.2.Fig. 98 ... borealis Thuneberg