THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 243 

 No. 178. DOLICHOPUS CELERIPES, new species. 



Male. ^Length 4 mm.; of wing 3.75 mm. Face rather wide, sil- 

 very white. Front green with brownish pollen which is almost 

 invisible but dulls the front. First and second antennal joints 

 yellow; third joint black, a little yellow at base, about as long as 

 wide, pomted at tip. Lateral and inferior orbital cilia yellow, about 

 five of the upper cilia on each side black. 



Thorax green with slight bronze reflections, dulled with brownish 

 pollen on the dorsum, this pollen more gray along the front; pleurae 

 dulled with white pollen. Abdomen green, dulled with white pollen, 

 which is more abundant on its sides. Hypopygium black; its 

 lamellae of moderate size, somewhat round, but a little longer than 

 wide, white with a rather narrow black border; jagged and bristly 

 at apex, fringed above with dark hairs which appear more or less 

 yellowish. 



Coxae yellow, middle pair a little grayish on outer side; anterior 

 surface with silvery pollen and very minute white hairs, still they 

 appear almost bare; the black bristles at tip rather weak. Femora 

 and tibiae yellow. The hairs on all femora unusually small, only a 

 few longer ones on upper edge of hind pair. Middle and hind femora 

 each with one preapical bristle, the latter without cilia below. Fore 

 tibiae besides the usual bristles with a long slender one at tip on the 

 posterior side which sometimes appears reddish and is fully two- 

 thirds as long as their basitarsi. Middle tibiae with one bristle 

 below, their basitarsi without a bristle above. Hind tibiae slightly 

 thicker than the others, the usual glabrous stripe on upper surface 

 poorly defined; lower edge with a row of bristle-like hairs below. 

 Fore and middle tarsi about one and a fourth times as long as their 

 tibiae, with the tips of the joints brown or blackish, darker at tip; 

 second joint about half as long as first, third a little shorter than 

 second, fourth and fifth of nearly equal length, fourth slightly shorter 

 than third. Hind tarsi blackish from the tip of first joint. Calyp- 

 ters, their cilia and the halteres yellow. 



Wings (fig. 178) grayish; costa with a conspicuous enlargment at 

 tip of first vein, which tapers into the costa; last section of fourth 

 vein a little bent near basal third; hind margin of wing scarcely 

 indented at tip of fifth vein, rather evenly rounded, the anal angle 

 being nearly obsolete. 



Female. — Face wide, silvery gray; third antennal joint a little 

 smaller than in the male; coxae, legs, tarsi and wings about as in the 

 male, except that there is no enlargment of the costa at tip of first 

 vein and no pale bristle at tip of fore tibiae like the one in the male. 

 The thorax is more metallic brown or blackish, but it seems to be 

 discolored in the only female we have. 



