292 Orthorihapha biachycera. 



Male. Vertex and frons grey. The head is smaller, especially 

 lower than in flavipes, and hence the frons is lower, and it is a little 

 broadened upwards. Epistoma white, likewise shorter than in favipes, 

 and very narrow below the antennæ; palpi pale yellow, somewhat 

 small. Occiput grey, with yellow bristles above, white hairs below. 

 Antennæ black, rather long, the third joint elongated, somewhat nar- 

 row, thrice as long as broad at the base and aboiit as long as the 



Fig. 133. Antenna of T. mactdipes. d". X 100. 



arista. Thorax brownish yellow pruinose; all bristles yellow, the 

 short bristles in front less distinet than in flavipes; only one distinct, 

 long dorsocentral bristle behind. Scutellum with two yellow bristles 

 and a smaller hair on each side. Pleura light grey pruinose; above 

 the middle coxæ a black, polished spot. Abdomen black, shining; 

 the front margin of the segments with a narrow, grey band, inter- 

 rupted in the middle. Abdomen is clothed with short, pale yellow 

 hairs. Venter black. Legs together with the coxæ dark or reddish 

 yellow, the tarsi, except metatarsus, brown; sometimes the posterior 

 femora somewhat brownish above. Front femora somewhat, middle 

 femora considerably thickened, but both pairs are, I think, a little less 

 thickened than in flavipes. The legs are yellowish haired, no bristles 

 on the front tibiæ, or these only very slightly stronger than the other 

 hairs ; the hairs below the hind femora a little finer than in flavip)es. 

 Wings hyaline or very slightly yellowish. Veins brown, paler at the 

 base. Halteres yellow. 



Female. Similar to the male ; the third antennal joint a little 

 shorter than the arista; abdomen pointed. 



Length 2,5—3 mm. 



This species is distinguished from flavipes especially by the longer 

 and more narrow third joint of the antennæ; also the smaller head 

 is somewhat characteristic, and likewise the colour of the tarsi; also 

 it seems that there are two notopleural bristles against three (generally) 

 in flavipes. All specimens I have seen had grey bands on abdomen, 

 and this is thus also characteristic for the species; finally it seems, 

 in contrast to flavipes., to have only one long dorsocentral bristle 

 behind. 



T. niacuHpes is much rarer in Denmark than flavipes-, Charlotten- 

 lund, Tyvekrog; the dates are ^^Ig — ^9. 



