May, 1803.] INSECTS OF THE DEATH VALLEY EXPEDITION. 253 



LIST OF DIPTERA OF THE DEATH VALLEY EXPEDITION. 

 By S. W. WlLLISTON. 



The following pages include a list of the species contained in a small 

 collection of Diptera from Death Valley and the adjoining regions, sent 

 me recently for determination by Prof. Riley. That the larger part of 

 them should be new to science is not at all strange, inasmuch as they 

 are, for the greater part, members of families which have been but lit- 

 tle studied in America. k The collection is of considerable interest as 

 adding three European or African genera hitherto unrecorded from 

 America, among which the wingless Apterina is the most remarkable. 

 After careful search I have found it necessary to describe two new 

 genera — one among the Dexiidse, the other an Ephydrinid. 



Culex inornatus n. sp. 



Female. — Palpi yellowish brown. Proboscis yellowish, black at the tip. Antenme 

 black, the basal joints yellowish. Occiput black, clothed mostly with whitish pu- 

 bescence. Thorax red, the dorsum reddish brown, thinly clothed with light yellow 

 and white tomentum, and blackish bristly hairs. Pleurae with white tomentum. 

 Abdomen black, somewhat yellowish in grouud-color on the second and third seg- 

 ments, covered with white scale-like tomentum on the front and sides of the seg- 

 ments, on the posterior part of the segments with blackish tomentum. Legs brown- 

 ish; on the inner side thickly, on the outer side thinly, covered with white tomen- 

 tum. Wings nearly hyaline, the tomentum of the veins blackish. Length, 5-6 mm . 



One specimen, Argus Mountains, April, 1891 (Koebele). Both this and the follow- 

 ing species belong to the genus Culex in the restricted sense of Lynch. 

 Culex n. sp. 



Female. — Dark brown or black, the occiput covered with white and brown tomen- 

 tum. Palpi black, at the tip silvery. Proboscis black, with a white ring beyond 

 the middle. Antennae black. Dorsum of thorax covered with brown and white to- 

 mentum, the white toward either side posteriorly, and forming two slender lines, 

 abbreviated anteriorly. Pleurae with white tomentum. Abdomen deep brown, Avith 

 six conspicuous rings of white tomentum on the anterior part of the segments, the 

 ground-color under them yellow; on the second segment a white tomentose spot in 

 front. Legs nearly black, the base of all the femora yellowish. On the outer side 

 of the femora, in large part, and along the whole inner side of the legs, as also moder- 

 ately broad rings at the articulations of all the tarsal joints, white. Wings nearly 

 hyaline; tomentum blackish, distributed nearly evenly on the veins. Length, 6 mm . 



One specimen, Argus Mountains, Calif., April. This species is closely allied to C. 

 annulatus Meigen, which occurs in the western regions and in Mexico, but seems to 

 differ in the uniformly distributed tomentum of the wings. 

 Simuliuni argus n. sp. 



Female. — Black, the legs in part light yellow. Front black, opaque. Face cinere- 

 ous, with whitish pubescence. Antennas brownish black, the basal joint yellowish. 

 Thorax black, the dorsum thinly polliuose, not shining; pleurae densely white polli- 

 nose, with a black spot. Abdomen opaque velvety black, the first three segments 

 with a narrow silvery white spot on either side at the hind margin; the next three 

 segments similarly marked, but the interval between the spots successively wider, 

 and each with two other, successively larger, white spots, leaving a black space in 

 the middle and a narrower one at the outer sides. Venter white. Legs brownish 



