Platvchirus. 



215 



slightly decreasing outvvards and all joints dilated; first joint a little 



longer than the two following; the two first joints are a little blackish 



marked below on the anterior side. Middle trochanters with short, 



black bristles at the apex ; the middle femora with short, 



yellow hairs on the antero-ventral side and with a 



little longer fringe behind, longest and generally dark 



towards the apex, but with no recurved hairs below 



apex; middle tibiæ very slightly dilated about the middle, 



with a short fringe on the basal half of the ventral 



margins, longest anteriorly; hind legs mainly with short, 



yellow hairs, a little longer on the antero-ventral side 



of the femora, and with a fringe on the anterior side 



of tibiæ, longest about the middle; hind metatarsi 



distinctly thickened. Wings somewhat strongly brownish 



tinged. Squarnulæ yellow to brownish, with a yellow 



fringe. Halteres yellow. 



Female. Frons narrower than in immar ginahis, 

 æneous, with two somewhat small, yellowish grey side 

 dust spots, connected at the eye-margin with the pru- 

 inosity on epistoma; it is yellow-haired but with dark 

 hairs across in front of the ocelli. Antennæ as in the 

 male. Thorax short-haired. Abdominal spots as in the 

 male or slightly smaller, fifth segment with two large 

 spots or quite yellow, sixth quite yellow. Legs coloured 

 as in the male, hind tibiæ quite yellow and hind meta- 

 tarsus less darkened. The hairs behind front femora all short, at the 

 base is the peculiar, white hair, but is is straight and somewhat short; 

 the hairs behind middle femora longish towards the apex and here 

 blackish. Squamulæ yellow. 



Length 7,5 — 9 mm. 



The pupa is quite similar to that of immar ginatus. 



This species is as usual easily known in the male by the shape 

 of the front tibiæ and the ciliation behind front femora ; in the female 

 it is known from the two preceding species by the quite yellow hind 

 femora and tibiæ, and from scambus by the presence of the white 

 hair at the base of front femora; in both sexes the antennæ are 

 characteristic and have the arista shorter than in scambus but longer 

 than in immarginatus. — It would seem that the pubescence on 

 epistoma and legs may vary somewhat in colour (as in most other 

 species), as Verrall describes epistoma as usually black-haired and the 

 fringe on hind tibiæ as black. 



P. fulviventris is rare in Denmark; Lersø, Dyrehaven (Stæger), 



Fig. 108. 



P. fulviventris^, 



right front leg 



from below. 



X 20. 



