42 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



Thorax dark green, slightly dulled with an almost invisible brown 

 pollen; pleurae with grayish pollen. Abdomen dark green with a 

 little white pollen* along its sides. Hypopygium black, its lamellae 

 (fig. 4a) yellowish at base, becoming black near their middle, some- 

 what triangular in outline, but rounded apically, scarcely jagged at 

 upper corner, fringed on apical border with short, delicate, little hairs. 



Legs wholly black. Fore coxae with black hairs on their anterior 

 surface. Middle and hind femora each with one preapical bristle, 

 the latter without cilia below. Hind tibiae only a little thickened, 

 their bristles long. All tarsi a little longer than their tibiae; middle 

 tibiae with a large bristle below; middle basitarsus without a bristle; 

 fore tarsi plain, the first joint about as long as the three following 

 taken together, the fifth joint appears to be a little yellowish. 

 Calypters and halteres yellow, the former with black cilia. 



Wings (fig. 4) dark grayish; costa scarcely thickened at tip of fifth 

 vein; last section of fourth vein bent a little before its middle; hind 

 margin of wing not indented at tip of fifth vein, almost evenly rounded; 

 anal angle rounded but rather prominent. 



Female. — Agrees with the male, except that the third antennal 

 joint is a little shorter and the hind tibiae a little more slender. The 

 face is nearly the same width as in the male and of the same sordid 

 white color; wings as in the male. 



Described from 1 pair taken by J. M. Aldrich in Idaho. 



Type, a male taken at Oxford; allotype, a female taken at Soda 

 Springs; both in the United States National Museum. 



Ty^^e.— Male, Cat. No. 22979, U.S.N.M. 



No. 5. DOLICHOPUS FORMOSUS, new species. 



Male. — Length 4 mm.; of wing 3.5 mm. Face rather narrow, 

 bright silvery white, a little narrowed below. Antennae wholly 

 black; third joint not much longer than wide, somewhat rounded at 

 tip, evenly rounded below; front shining green; lower orbital cilia 

 silvery white. 



Thorax dark shining green with blue reflections, or wholly blue; 

 pleurae dulled with white pollen. Abdomen dark green with black 

 incisures and a little white pollen along its sides. Hypopygium 

 black; its lamellae (fig. 5a) of moderate size but rather long, some- 

 what triangular, tapering into the stem, but rounded at apex, whitish 

 with a black border of moderate width, not at all jagged, fringed 

 with delicate little hairs which are brown except on lower part of the 

 stem. 



Coxae, legs and feet wholly black; femora with green reflections; 

 knees slightly yellowish. Fore coxae with black hairs on their front 

 surface. Middle and hind femora each with one preapical bristle, 

 the latter not ciliate below. Hind tibiae but little thickened. Fore 



