602 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxiu. 



thicklv 'covered with depresised light yellow hair>; and brown and yellow long 

 marginal hairs; legs light yellow, apices of middle and hind femora and bases 

 f)f their tiV)ia3 pale Itrownish, outer side of all tibiie and iipjjer side of hind 

 tarsi beset with many unusually long yellow hairs; knobs of halteres yellowish 

 white; wings hyaline, narrow and rather long; length, l.o to almost 2 mm. 



pergdiidei, new species. 

 A specimen of each sex, collected March 10 by Mr. Th. Pergande, for whom the 

 species is named. Washington, District of Columbia. 



Tv^x.— Cat. No. 5463, U.S.N.M. 



11. Apex of third vein near two-thirds or three-fourths length of wing, eyes con- 



tiguous 1-t 



Apex near middle of length of wing, fourth forking beyond the small cross vein, 

 empodia wanting 12 



12. Wings not distinctly spotted, eyes contiguous 13 



Wings covered with whitish hyaline and dark gray spots. Head black, eyes 



rather widely separated, antennte black, base of flagellum yellowish, its joints 

 except last two of nearly an equal length, noticeably longer than broad, mouth 

 parts black; body black, opaque, mesonotum gray pruinose and covered with 

 brown spots, halteres and legs brown, tibiae bearing several rather long yellow 

 hairs on outer side, a yellow ring before ajjices of front and middle femora and 

 near bases of their tibise, tarsi largely yellow; wings nearly wholly covered 

 with brown hairs, third vein contiguous to the first and to the costal vein, 

 apical portion of first and third veins and costal vein near them greatly dilated, 

 forming a darker spot than any of the others, fourth posterior cell whitish hya- 

 line except a central triangular gray spot extending to the outer angles; length 



nearl V 2 mm variipennh, new species. 



Three female specimens. Westville, New Jersey (July 2, C. W. Johnson) ; Rich- 

 mond, Virginia (Mrs. A. T. Slosson); and Mexico City, Mexico (O.W.Barrett). 



TyjM'.— Cat No. 5464, U.S.N.M. 



13. Mesonotum wholly densely gray pruinose, marked with three indistinct dark 



vittfe. Head black, antennae and proboscis brown, palpi yellow; body black, 

 the humeri, a large spot on pleura beneath wing, the scutellum, hind margins 

 of abdominal segments, and the venter, yellow; halteres and legs yellow, sutures 

 of the joints of latter brown; wings hyaline, almost wholly covered with brown 

 hairs, third vein coalescing with the first nearly to apex of the latter, then 

 extending close to the costa for a short distance; length, 1 mm. 



griseus, new species. 

 Two female specimens. Washington, District of Columbia (June 9, H. S. Bar- 

 ber); and Lake Worth, Florida (Mrs. A. T. Slosson). 



T(/j)e.— Cat. No. 5465, U.S.N.M. 



Mesonotum opaque black, somewhat velvety, in certain lights thinly whitish 

 pruinose. Head and its members black, hairs of male antenna' brown, their 

 apices whitish, body black, humeri, scutellum, and halteres light yellow, legs 

 dark yellow; wings hyaline, almost wholly covered with brown hairs, third 

 vein coaleseent with the first nearly to apex of the latter, then extending a 

 short distance close to the costal vein; length, 0.5 mm.. mutabUis, new species. 



Five males and 14 females. Washington, District of Columbia (on windows, 

 June 5 to 8, H. 8. Barber); and Jacksonville, Florida (Mrs. A. T. Slosson). 



Type.— Cut. No. 5466, U.S.N.M. 



