THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 45 



tending beyond its tip; last section of fourth vein bent at its middle; 

 hind margin of wing not indented at tip of fifth vein; anal angle 

 prominent. 



Female.— Feice a little wider, silvery white; orbital cilia yellowish 

 white; the pollen of the face not extending above the antennae; 

 thorax and abdomen very bright shining green with some coppery 

 reflections on the latter; calypters with white pollen. 



Described from 1 pair taken at Oxford, Idaho, by J. M. Aldrich, 

 and 1 male taken at Bozeman, Montana, June 25, 1900, by E. Koch, 

 at an elevation of 4,800 feet. 



Type.— Male, Cat. No. 22982, U.S.N.M., from Oxford, Idaho. 



The male of this form differs from squamosus in having the lamellae 

 of the hypopygium very much smaller, the face a little wider and 

 much shorter, and its pollen not extending above the antennae as in 

 that species. The female of viridis differs from that of squamosus 

 in having the silvery pollen of the face end at the antennae; in squa- 

 mosus it extends widely and conspicuously along the orbits nearly to 

 the vertex. 



No. 8. DOLICHOPUS NIGRIMANUS, new species. 



Male. — Length 3.75 mm.; of wing 3.25 mm. Face of moderate 

 width, a little narrowed below, silvery white. Front dark green. 

 Antennae wholly black; third joint small, about as long as wide, 

 somewhat orbicular in outline but a little pointed at tip. Lateral 

 and inferior orbital cilia white, about six of the upper cilia on each 

 side black. 



Thorax dark shining green; pleurae dulled with gray pollen. 



Abdomen green with the hind margins of the segments black, 

 sometimes there are coppery reflections before the black margins; 

 the white pollen on its sides not abundant. Hypopygium black; 

 its lamellae (fig. 8(x) moderately large, somewhat triangular in out- 

 line, but rounded at tip, white with a rather narrow black border on 

 the apical margin, which is jagged and bristly. 



Coxae, legs, and feet black, knees only a little yellowish. Middle 

 and hind femora each with one preapical bristle, the latter not ciliated 

 below. Posterior tibiae thickened, especially toward their tips. 

 Fore tarsi a little longer than their tibiae; first joint nearly as long 

 as the remaining four joints taken together, second joint nearly as 

 long as third and fourth taken together, the third being about two- 

 thirds and the fourth one-third as long as the second. Middle tarsi 

 a little longer than their tibiae, their basitarsus being without a 

 bristle above. Calypters and halteres yellow, the former with black 

 cilia. 



Wings (fig. 8) grayish, tinged with brown in front of third vein; 

 costa not enlarged at tip of first vein; last section of fourth vein 

 bent near its middle; third vein bent backward at tip; hind margin 



187329—21 4 



