54 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
and of nearly the same width. Cheeks black, with short black pile. 
Occiput silvery gray pollinose, white pilose, with black bristles. 
Dorsum of thorax and scutellum densely silvery gray pollinose, 
sparse reclinate yellowish white pilose. In certain lights there is a 
brownish caste to the mesonotum. Broad lateral margins of the tho- 
rax and margin of scutellum shining black; scutellum with four mar- 
ginal bristles. Pleura largely silvery gray pollinose, white pilose, the 
pteropleura semishining black Halteres bright yellow, the base of 
the stem light brown. 
Abdomen shining black, first segment silvery gray pollinose, a nar- 
row posterior rim on the second and third, and spots on the sides of 
the fifth silvery. Reclinate white pile on the first three segments, 
longer on the first; beyond the third segment short erect black pilose 
as usual. Venter gray pollinose on the first three segments. Fore 
legs black, also the four hind femora; the middle and hind tibiae red- 
dish, darker at the tips; the middle and hind tarsi largely reddish, 
black apically; bristles of the legs black. Wing veins yellow and 
brown, the wing membrane yellow at the base, beyond this largely 
pale grayish brown; costal cell and stigma yellow; cells near the base 
of wing largely hyaline; cell M-3 closed near the wing margin. 
Type locality.—Bill Williams Fork, Arizona. 
Type.—tIn the Kansas University collection. 
Distribution.—The distribution according to three females is: Cali- 
fornia—Compton; Los Banos, May 22 (i. P. Van Duzee), [Cal. Acad. 
Sci.]; Claremont (Baker), [Pomona College]. 
The writer first described the species as new, but Kréber’s rede- 
scription of both sexes in his 1914 paper clearly places the species. 
It is near aldrichi and laevigata, and is recorded by Kréber from 
Death Valley, California, and Colorado. 
PSILOCEPHALA MUNDA Loew. 
Plate 6, fig. 46; plate 7, fig. 73; and plate 8, figs. 81 and 96. 
1869. Psilocephala munda Lorw, Berlin. Ent. Zeit., vol. 12, p. 9. 
1869. Psilocephala melanoprocta Loew, male, described in the same publica- 
tion, p. 11. 
Male.—Length 7 to 8 mm. Head, including antennae, palpi, and 
proboscis, black. The antennae short, third joint longer than the 
first two combined and considerably wider, tapering and with a small 
style (fig. 73); strong bristles of first two antennal joints black. 
Occiput gray pollinose above, white below. Cheeks, occiput, and 
palpi white pilose, the vertex with black pile; face and large frontal 
triangle silvery white pollinose. 
Thorax black, the mesonotum dull, gray-black with two narrow 
white vittae, lateral margins gray pollinose; pile erect, mixed black 
and white. Two pairs of praescutellar bristles and four bristles on the 
