92 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL. 62. 
semishining. There is no black pile on the antennae. The first 
abdominal segment is gray pollinose, the sides of the second semi- 
shining. The upper forceps of the genitalia are largely black. The 
genitalia are figured on plate 11. 
A female sent with the above specimen was taken in the same 
locality. The female is strikingly different from the male and is 
described below: 
Female.—Length 7.5 to 8.5 mm. Head black, frons with a few 
short black hairs and a line of black pile on upper side of face and 
outer margin, the rest of the face, cheeks, and occiput with long 
white pile. Occiput and face gray pollinose, the post-ocular bristles 
black. Two very large, round, shining black calli on lower half of 
frons (fig. 125); upper half of frons and vertex flat, brownish gray 
pollinose. Antennae black with black bristles, more or less gray 
pollinose, especially the first two joints, the first joint slightly longer 
than the third and with white pile on the basal half. 
Thorax opaque grayish black, reclinate whitish pilose and with 
some erect brownish pile. Mesonotum with two faint gray stripes. 
Seutellum colored like the thorax, with reclinate white pile and four 
black bristles. Pleura and coxae black, yray pollinose, white pilose. 
Halteres blackish, including the stem. 
Abdomen largely shining black, the first two segments thinly white 
pilose, the other segments short, erect, rather dense black pilose; 
second segment with a distinct white border, a very narrow one on 
the third segment; second and third segments more or less gray 
pollinose on sides and posterior margins, gray pollen above on the 
fifth. Venter gray pollinose, thinly so beyond the fourth segment, 
black pilose beyond the second. Tibiae and first tarsal joints except 
the apices yellowish red, the legs otherwise black, with black bristles; 
femora with reclinate silvery white pile and some erect white pile, 
more dense on the front pairs; front and middle femora with three 
bristles below. Wings hyaline, the veins heavy and black, the 
stimga brown; r—m cross vein faintly clouded, cell M-3 closed and 
petiolate. (Fig. 156.) 
Neallotype-—Female, collected at Alamogordo, New Mexico, May 
5; L902. No.663 [Ac Neo: ]: 
Specimens examined.—One male, three females. 
The four specimens seen by the writer were all from New Mexico. 
The sexes are so different that until they are actually taken together 
there will be some doubt as to their belonging to the same species. 
Coquillett records taking 10 specimens at Kukak Bay, Alaska, and 
Krober records the species from southern Colorado. 
