102 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



the apicals and both smaller than the strong intermediate pair; pre- 

 apicals present. Abdomen black, sides of first and second segment 

 dull-reddish; last three segments with a poUinose band on the basal 

 half, which is invaded from behind by many bristly hairs; first two 

 segments each with a median marginal pair of bristles, the third with 

 a median marginal pair and two or three laterals, the fourth with a 

 marginal row of about ten bristles; macrochaetae of middle segments 

 of the same size as those of fourth segment. Genitalia black, in 

 repose largely concealed within tip of abdomen and not visible from 

 the side. Wings hyaline; hind cross vein nearly parallel to section 

 of fourth vein beyond the bend; costal spine lacking; one bristly hair 

 at base of third vein. Legs black; pul villi of fore feet less than one- 

 fourth length of last tarsal joint; middle tibia with a single bristle on 

 outer front side near the middle ; hind tibia with four to five unequal 

 bristles on outside extending to slightly beyond the middle. 



Length, 4.0 mm. 



Type.— M&le, Cat. No. 28164, U.S.N.M. 



Host relationships. — Unknown. 



Described from a single male from Horseshoe Bend, Idaho, col- 

 lected by Dr. J. M. Aldrich in 1900. 



GYMNOPROSOPA INFLATICOKNIS, new species 



Female. — Front at narrowest 0.4 of the head width from measure- 

 ments of two which were 0.40 and 0.40 respectively; frontal vitta 

 yellow, sides parallel or shghtly expanded at the middle where width 

 of vitta is three times that of parafrontal; parafrontals gray polli- 

 nose, merging into silvery pollinose on face and bucca; about ten 

 bristles in the frontal row, those at the back scarcely larger than the 

 parafrontal hairs which are most densely grouped just anterior to 

 the lowest ocellus, where a few hairs occur on the frontal vitta be- 

 tween the frontal rows; one reclinate and tliree or four proclinate 

 orbital bristles; vibrissae level with front edge of oral margin; 

 facial ridges with a small cluster of bristly hairs on the lowest fifth; 

 antennae extend five-sixths distance from their base to the vibrissae; 

 second joint brown; third joint black, inflated saclike, conspicuously 

 pitted, not pointed at the outer apical angle, from three and one- 

 half to four times length of second joint; arista thickened on basal 

 half; parafacials sparsely beset with black bristly hairs, continuous 

 from parafrontals; in profile, bucca equals one-third eye height; 

 proboscis (hstinctly shorter than head height; palpi clavate, yellow 

 with blackish tips. Thorax gray poDinose over black, ^\dth three 

 obscure vittae; scutcllum with three pairs of marginal bristles of 

 about equal size and a somewhat smaller preapical pair. Abdomen 

 shining black, last tliree segments with wliite pollinose bands sharply 

 defined from the black and confined to basal half of the segment but 



