114 Amials Entomological Society of America [Vol. XII, 



There is no record that Erax similis has been recognized 

 since it was described by WilHston and we have good reason to 

 believe that it is the female of tagax. 



Erax leucocomus WilHston. 



A large pale species with bristles and hairs of head, thorax and 

 abdomen all pale yellowish; legs usually with black femora and black 

 bristles throughout; wings delicate yellowish, veins quite distinctly 

 yellow on the basal part. Total length 25 to 30 millimeters. Male 

 wing with the furcation of the third vein beyond the base of the second 

 posterior cell, stump about as long as the basal section, costa not 

 dilated in the least. Hypopygium large from dorsal view gradually 

 widened toward the tip, where it is much wider than in other species 

 of its group. The abdomen in both sexes is pale yellowish gray without 

 markings, but somewhat changeable according to the direction from 

 which it is viewed. In the male, segments six and seven may be said 

 to be silvery and in the female segment seven is somewhat darker than 

 the others. Oviduct black. Nearly as long as the last three abdominal 

 segments. 



Ten specimens from Western Kansas, collected by F. X. 

 Williams and one from Dallas, Texas, taken September 5, 1905, 

 by F. C. Bishop. 



The species is very distinct and readily recognized but ap- 

 pears to be rare and I had two species questionably referred to 

 leucocomus before I procured it. It would not be strange if some 

 specimens would have some black bristles on the body. It is 

 well adapted to life on the sand on account of its color. 



Erax quadrimaculatus Bellardi. 



Total length 2S to 34 millimeters. Mystax rather sparse, composed 

 largely of black bristles with a few pale ones and pale hairs intermixed, 

 beard nearly white. Whole body black and appearing darker than 

 other species of Erax. Thorax very sparsely gray pollinose with black 

 bristles and hairs, scutellum with short black hairs on the disc and two 

 to four black bristles on the margin ; femora, tarsi and apexes of the tibiae 

 black, remainder of tibiae pale yellow, wings uniformly fuscous all over, 

 costa only slightly dilated in the male, furcation of the third vein clearly 

 beyond the base of the second posterior cell. In the male abdominal 

 segments two, three, four and five with sides narrowly gray pollinose, 

 extended dorsally on the posterior margin of each, but not uniting 

 across the dorsum; segment six silvery on each side, widest before 

 leaving a black dorsal triangular spot with its base on the posterior 

 margin; segment seven similar, but the silvery areas much reduced and 

 the black consequently extended. Female segments two, three and four 

 as in the male, five conspicuously silvery on each side, black on the 

 mid-dorsum ; six and seven velvety black, oviduct black, hardly as long 

 as abdominal segments five, six and seven. 



