100 BULLETIN 116, UNITED STATES NATIONAL MUSEUM. 



pressed. Middle tarsi a little longer than their tibiae. Middle and 

 hind tarsi black from the tip of the first joint. Hind tarsi wholly 

 black. Calypters and halteres yellow, the former with white cilia. 



Wings (fig. 56) slightly tinged with gray; costa with a knotlike 

 enlargement at tip of first vein; last section of fourth vein rather 

 sharply bent at its basal third; tips of third and fourth veins rather 

 far apart; hind margin of wing deeply notched at tip of fifth vein; 

 anal angle rounded, not very prominent. 



Described from 4 males; 1 was taken at Kanaka Bay, San Juan 

 Island, Washington, May 31, 1906, by J. M. Aldrich; 2 I took at 

 Sacramento, California, June 4, 1915, and 1 taken by E. P. Van 

 Duzee, at Crystal Lakes, San Mateo County, California, June 25, 1916. 



Type.— MsAe, Cat. No. 23005, U.S.N.M., from Sacramento, Cali- 

 fornia. 



No. 57. DOLICHOPUS UMBROSUS, new species. 



Male. — Length, 4.7 mm.; of wing, 4.5 mm. Face wide, silvery 

 white, slightly tinged with yellow on upper part. Front dark 

 shining green. Antennae wholly black; third joint large, twice as 

 long as wide, pointed at tip, nearly straight above, rounded below 

 to the tip; arista a little longer than the antennae, inserted just 

 beyond the middle of the third joint. Orbital cilia wholly black. 



Thorax dark green; anterior part of dorsum duU in type specimen, 

 apparently from brown pollen, posterior part and scutellum shining; 

 pleurae dulled with whitish pollen. Abdomen dark green with slight 

 coppery reflections, incisures black. Hypopygium black, very small; 

 its lamellae dark yellowish, edged with black and fringed with short 

 black hairs, somewhat oval in outline, but narrowed into the stem; 

 the hypopygium (fig. 57a) including its lamellae only reaching the 

 posterior ventral edge of the second abdominal segment. 



Coxae black with silvery pollen, their extreme tips and trochanters 

 yellow; fore coxae with black hairs on the anterior surface. I'ore 

 and hind femora black, the former broadly, the latter narrowly 

 yellow at tip. Middle femiora black at base, dark yellow at apex, 

 the yellow extending nearly to the base on the sides, but the black 

 reaching three-fourths their length on lower edge and shading into 

 brownish yellow. Middle and hind femora each with two preapical 

 bristles, placed one before the other, the latter not ciliated below, 

 but with a row of rather long hairs on lower outer edge. Tibiae 

 yellow; posterior pair not thickened, black for one-fourth their 

 length, the black not well defined, the glabrous stripe on upper 

 edge distinct. Fore tarsi a little longer than their tibiae, dark 

 yellow, blackish above from the tip of the first joint. Middle and 

 hind tarsi wholly black; the former about one and a half times as 

 long as their tibiae, with fourth joint very slightly flattened, more 

 than twice as long: as fifth, their basitarsi without a bristle above. 



