10 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.63, 



with two rows of large bristles ; middle pair yellow, their base brown, 

 usually distinctly so for one-third their length, they have one bristle 

 below and two rows of long ones above. Hind tibiae black with 

 upper edge a little yellowish. Fore tarsi yellow, darkened at tip; 

 first two joints of nearly equal length, covered with minute yellow 

 hairs, both with their tips enlarged. Middle tarsi yellowish, tips 

 of the joints dark. Hind tarsi black with first and second joints of 

 nearly equal length. Calypters, their cilia and the halteres pale 

 yellow. 



Wings nearly hyaline; third vein gently bent backward at tip; 

 last section of fourth vein bent near its middle, parallel with third 

 at tip; last section of fifth vein scarcely more than one and a half 

 times as long as the cross-vein. 



Female. — What I take to be the female of this species has its face 

 wide, the pollen of the face white, sometimes a little yellowish on 

 upper portion, the suture just below the center, its oral edge a little 

 pointed in the middle. Front green with considerable white pollen. 

 Antennae small, about as long as wide ; arista about three times as 

 long as the antenna. Beard white, rather abundant on the sides. 

 Abdomen with black hairs on the dorsum, those on the sides pale, 

 long on the first two segments. Thorax with a spot of white pollen 

 back of the humeri. Fore coxae with pale hair. Femora black with 

 yellow tips, anterior ones with rather long pale hair on posterior 

 surface ; middle ones with a few pale hairs at base below, three pre- 

 apical bristles on posterior and one on anterior surface ; hind femora 

 with the one preapical bristle. Tibiae yellow; hind ones slightly 

 brownish at tip; middle tibiae with a row^ of three long bristles on 

 lower anterior edge. Fore tarsi mostly yellowish, middle ones more 

 brownish almost to their base, hind ones wholly black with their 

 first and second joints of equal length. Wings about as in the male, 

 except that they are dark grayish. 



Described from 5 males and 16 males taken at Fairbanks, July 

 1-4. 



ry;?e.— Male, Cat. No. 25960, U.S.N.M. 



PORPHYROPS ALBIBARBA, new species. 



Male. — Length, 4 mm. ; of wing the same. Face narrow, silvery 

 white. Palpi velvety black, edged with white pollen, and with a 

 few small black hairs. Front steel-blue, dull. Antennae black 

 (fig. 7) ; third joint about as long as the face, rather slender toward, 

 the tip; arista slightly more than half as long as the antenna, its 

 first joint short. The long black orbital cilia reaching down to upper 

 fourth of eye height, below these the long, dense beard is sordid 

 white. 



Thorax blue-green, dulled with gray pollen ; dorsum with the usual 

 brown stripe on each side of the acrostichal bristles; scutellum with 

 one pair of long bristles, two pair of small ones between them, and 



