– All coxae and femora mostly black, hairs and bristles on fore coxa white ... 3

3. Acrostichal setae microscopic; face at narrowest point as wide as ocellar tubercle; face under antennae 1.5 times wider than height of postpedicel; apical section of CuA₁ shorter than basal section measured from anal cell; 1.75-2.0.Fig. 18 ... laesus (Wiedemann)

– Acrostichal setae well developed, their length about equal to distance between rows; face narrower; face under antennae at most as wide as height of postpedicel; apical section of CuA₁ longer than basal section measured as above ... 4

4. Mid tibia with 2 strong anteroventral bristles; palpus with light setae at apex; 2.2-2.7.Fig. 29 ... arcticus Frey

– Mid tibia with 1 strong bristle ... 5

5. Facial triangle prolonged forwards into an extremely narrow strip, hardly as wide as diameter of front ocellus; palpi somewhat longer and rounded at tip, where it bears a few pale hairs; thorax and scutellum usually with slight violet reflection; fore tibia and pubescence on legs pale yellow; 1.5-2.5.Fig. 20 ... suavis Loew

– Prolongation on facial triangle distinctly wider that front ocellus; palpi more triangular, almost pointed at tip, where there are rather more numerous fine black setae; thorax and scutellum without violet reflection; fore tibia and pubescence on legs more brownish yellow; 2.0-2.25.Fig. 28 ... palustris Verrall

6. Femora entirely or mainly yellow ... 7

– Femora entirely or mainly black ... 8

7. All femora entirely yellow; fore coxa usually entirely black-haired; hind margin of wing between CuA₁ and A₂ straight or even concave, then forming distinct bulge immediately before CuA₁; 2.5-3.0.Fig. 19 ... neglectus (Wiedemann)

– Hind femur broadly black at apex; fore coxa at least partly pale-haired; hind margin of wing normal, uniformly convex; 1.75-2.5 (see above) ... cilipes Meigen

8. Hind trochanter, often also base of femur, clear yellow ... 9

– Hind trochanter black or brown, at palest never clear yellow ... 11

9. Postpedicel quite twice higher or at least 3 times larger than pedicel; pulvilli of fore and mid legs hardly developed; hind tibia not remarkably ciliated on anterior side; 1.5-2.75.Fig. 22 ... pulchellus Kowarz

– Postpedicel smaller, not more than 2.5 times larger than pedicel ... 10

10. Empodium and pulvilli of fore tarsus strongly developed; hind tibia strongly ciliated on anterior side; the cilia twice longer than diameter of tibia; 2.5.Fig. 25 ... femoratus Zetterstedt

– Empodium and pulvilli of fore tarsus reduced; hind margin of wing distinctly convex immediately before CuA₁; 2.0.Fig. 30 ... ringdahliParent

11. Fore coxa mainly, and trochanter entirely, dirty white; legs otherwise black; 2.5-3.Fig. 24 ... cupreus Macquart

– At least fore coxa mainly black ... 12

12. Fore tibia rusty brown, ciliated above and below; some ventral cilia distinctly longer than diameter of tibia; mid tibia brownish black; 2.5-3.25.Fig. 23 ... blepharosceles Kowarz

– Fore tibia only shortly ciliated, or if cilia longer than normal, then fore and mid tibiae clear yellow ... 13

13. Postpedicel distinctly reniform, large, at least twice as high as pedicel; all tibiae black or brown; mid tibia with 2 long anterodorsal bristles; 2.5.Fig. 27 ... obscuripes Zetterstedt 

– Postpedicel smaller ... 14

14. Legs mostly black with fore trochanter, fore and mid knees brownish or reddish yellow, fore and mid tibiae brownish black; hind tibia not ciliated; 2.0 ... melampodius Loew

– At least fore and mid tibiae entirely or mainly yellow to rusty yellow ... 15

15. Postpedicel distinctly triangular, with rounded point at tip; 2.25.Fig. 21 ... angulicornis Kowarz

– Postpedicel not triangular, more reniform and without trace of point at tip; 2.0-2.75.Fig. 26 ... gramineus (Fallén)