Key to Palearctic Medetera species groups formerly regarded as genus Oligochaetus

1 Postoculars irregular, not uniseriate; wing milky, with brownish spots; mid tibia with 3 apical setae, one of them nearly as long as mid basitarsus .................................................................................................. vlasovi species group

- Postoculars regularly uniseriate; wing hyaline, without spots; mid tibia with short apical setae................................. 2

2 Distal part of CuA1 5–6 times longer than cross-vein m-cu; basal part of CuA1 somewhat thickened along nearly whole length; male cercus short, at most half as long as surstylus, without cilia.................... spinigera species group

- Distal part of CuA1 at most 3–4 times longer than cross-vein m-cu; basal part of CuA1 not thickened; male cercus longer, covered with cilia ............................................................................................................................................. 3

3 Face and clypeus distinctly heterochromous, with the face brown or greyish pollinose and clypeus more or less shin- ing ............................................................................................................................................................................... 4

- Face and clypeus entirely dusted, monochrome .......................................................................................................... 5

4 Femora mostly black; postocular and proepisternal bristles whitish......................................... micacea species group

- Femora mostly yellow; proepisternal bristles black, postoculars partly black ..................... annulitarsa species group

5 Legs mainly yellow; male cercus without strong spiniform apical seta ................................. plumbella species group

- Legs mainly black; male cercus with a strong spiniform apical seta......................................... senicula species group