THE DIPTEROUS GENUS DOLICHOPUS IN NORTH AMERICA. 107 

 No. 63. DOLICHOPUS OPPORTUNUS, new species. 



Male. — Length 5.3 mm.; of wing 5 mm. Face rather narrow, 

 widening a little from the middle upward, silvery white. Front shin- 

 ing green. Antennae (fig. 6.3Z>) black, third joint small, but little 

 longer than wide, rounded at tip. Orbital cilia wholly black. 



Thorax green with slight coppery reflections on the sides of the 

 dorsum ; the carina running from the humeri to the root of the wings 

 yellowish brown with a small reddish spot at the humeral end; 

 pleurae more black with gray pollen. Abdomen green with coppery 

 reflections, its incisures narrowly black; extreme lower edges of the 

 dorsum on first and second segments more or less yellowish; the 

 white pollen on its sides forms spots on the sides of the segments. 

 Hypopygium black; its lamellae (fig. 63a) rather large, rounded, but 

 narrowing into the stem, about as long as broad, whitish with a very 

 narrow brown margin above and wider black border on the jagged 

 apical margin, which is fringed with long bristlelike hairs. 



Coxae black with yellow tips and silvery pollen; anterior pair with 

 delicate white hairs on the front surface. Anterior femora black 

 with their tips narrowly yellow. Middle femora yellow, blackened 

 at base on upper and lower edges for about one-third their length. 

 Posterior femora yellow, with the tip and base black and narrowly 

 black on upper edge. Middle and hind femora each with two pre- 

 apical bristles, placed one before the other, the latter nearly baie 

 below. All tibiae yellow; the posterior pair black at tip for one- 

 fifth their length, slightly thickened apically. Fore and middle tarsi 

 about as long as their tibiae, brown from the tip of the first joint, 

 the former with the joints of regularly decreasing length, first joint 

 scarcely as long as the three succeeding joints taken together. Hind 

 tarsi wholly black. Calypters and halteres yellow, the former with 

 black cilia. 



Wings (fig. 63) tinged with brown, which color is deeper in front 

 of the third vein, and with distinct' clouds on the cross vein and at 

 the bend in the fourth vein; costa scarcely thickened at tip of fifth 

 vein; last section of fourth vein bent at its second fifth; beyond this 

 bend the third and fourth veins are nearly parallel; hind margin of 

 wing a little indented at tip of fifth vein, rather evenly rounded, the 

 anal angle not beuig very prominent. 



Female. — Face wide, white; third antennal joint nearly round in 

 outline, still a little pointed at tip ; fore coxae with white hairs on the 

 anterior surface, mixed with a few black ones along the inner edge. 

 Otherwise about as in the male. Middle tibiae with one bristle 

 below, their basitarsi without a bristle above. 



Described from 3 males and 4 females, taken by J. M. Aldrich at 

 Hagerman, Idaho, July 1, 1900. 



Type.— Kale, Cat. No. 23010, U.S.N.M. 



