June, 1913-] AlDRICH : NORTH AMERICAN SpECIES OF LiSPA. 135 



from below, the lower projecting edge of the front is black from the insertion 

 of the antenna obliquely upward to the eye. Antennae velvet black, third 

 joint hardly twice as long as the second and more slender than it, arista 

 thickened on the basal third and with about a dozen long hairs, none originat- 

 ing beyond the middle. Sides of face silvery above on the outside of the 

 ptilinal suture, the rest brassy, hairy outside the suture from the middle of 

 the silvery part to about the lower corner of the eye. Palpi rather dark yel- 

 low, enlarging with moderate suddenness toward the tip, of medium size for 

 the genus, hairy all over except a small space beyond the middle. Proboscis 

 black, shining. Back of head convex, more so below, gray with bushy black 

 hair, which is especially long on the oral margin ; occiput with hairs above 

 and a pair of post-vertical bristles, bare below these. 



Thorax gray, with black hair almost all over, bristles as usual in the 

 genus; pleura concolorous with dorsum, bare behind the front and middle 

 coxse and in front of the prothoracic spiracle. Calyptcrs wax-white with 

 yellow border. Halteres with brown knob, stem yellow. 



Abdomen robust, gray all over the first four segments, slightly yellowish 

 above, with long hair; along the sides some macrochstae are hardly dis- 

 tinguishable from the large hairs ; 4th segment with a terminal circle of 

 machrochsetae and a discal row that is interrupted in the middle; 5th segment 

 velvet black, hairy, with a conspicuous median dorsal chalk-white spot. 



Legs very hairy, gray throughout, the tarsi more blackish with pale yel- 

 low pubescence below, pulvilli pale yellow. Front legs : coxae with a row of 

 strong bristles on anterior side ; femora with a double row of bristles on upper 

 outer side and a single row on lower ; middle femora with two preapical 

 bristles; middle tibiae with two bristles near the middle; hind femora with the 

 usual rows of long bristles and besides them numerous very long hairs below 

 on the basal two thirds ; hind tibiae exactly equal to their tarsi in length, with 

 one bristle near the middle. All the tarsi have the basal joint shorter than 

 the other four combined, the latter of approximately equal length in each 

 tarsus. 



Wing subhyaline, veins yellowish toward the base, 3d and 4th veins not 

 convergent. 



Female. — Head about 2.06 times front in width ; abdomen with a dark 

 median line (sometimes faintly visible on the basal segments in the ^), and 

 sub-shining blackish lateral spots on the hind margin of the second and third 

 segments ; the median stripe is usually widened on the anterior part of the 

 second and again on the third segment ; 4th segment entirely sub-shining 

 blackish ; sth segment minute, black. No long pile on under side of hind 

 femora. Length, (^, S-S-7-2 mm. ; $, 6.5-9.5 "''"■'• 



Many specimens of both sexes : South end of Great Salt Lake, 

 Utah, July 31, 1908 and July 9, 1911 ; Pyramid Lake, Nevada, July 16, 

 191 1 ; Walker Lake, Nevada, July 25, 191 1; Borax Lake in Lake Co., 

 California, August 8, 191 1. 



