SIMULIUM. 53 



Two females marked Colorado, No. IGO.") (C. F. Baker) ; one female 

 Pecos, X. Mex., June 28, on horse (M. Grabham) ; and three females 

 Inyo County (?), Cal. (A. Davidson). 



The first mentioned specimens are the type lot and are slightly 

 smaller than those from California. 



Male. — P2yes of the normal form of the males in this genus ; face 

 white-pollinose, antennae brown, paler on basal two joints; postocular 

 cilia pale. Scutum with white pollinosity, which is distinctly pearl- 

 aceous on anterior margin ; the whole disk poUinose except a poste- 

 riorly abbreviated, central, longitudinal, opaque black stripe, and 

 faint indications of two much shorter lateral stripes; pilosity hair- 

 like, white; prescntum yellow; pleurae brown, darker on center; 

 scutellum 3'ellow. Abdomen opaque black; segment below basal 

 scale 3'ellow, fifth segment and postero-lateral margins of the apical 

 segments yellow. Legs colored as in female, but the hind femora are 

 only darkened at apices, and the claws are trifid. In other respects 

 similar to female. One specimen, Colorado, Xo. 1605; no other 

 data. It bears the t5^pe label " Cat. Xo. 10381 U. S. X. M." 



The early stages are unknown. 



Simulium vittatum Zetterstedt. 



Female. — Gray, opaque, or opaque black with very thick gray 

 dusting, except on the portion of body given as black in description. 

 AntennjB brown, basal two joints yellowish; palpi and proboscis 

 brown. Scutum with a straight dorso-central stripe which is some- 

 times linear, but generally with a brownish suffusion, broadest at 

 anterior third; this stripe reaches the anterior margin and stops at 

 about posterior fourth; on either side of this central stripe there is 

 a bicurved stripe which is triangularly dilated at anterior extremity, 

 then much narrowed, bent inward on anterior half, and bent out- 

 ward and slightly dilated on its posterior half, joining the central 

 stripe, or almost so, with an inward curve at posterior fourth ; later- 

 ally beyond these two stripes are other two which stop much short 

 of the prescutum, and also of the end of central stripe; generally 

 these outer stripes are dilated anteriorly; pleurte unicolorous gray; 

 scutellum slightly darkened on disk. Abdomen with basal scale with 

 a black central spot; first, second, and third segments with a basal 

 crossband of black which is produced centrally; the next three seg- 

 ments with a posteriorly tridentated, black crossband; the fourth 

 and fifth with an additional lateral black spot; apical segments 

 darkened. Legs black, all tibiae whitish yellow on basal half, the 

 division between the colors generally very abrupt, mid tarsi with 

 basal joint yellow or whitish at base, hind tarsi with two basal joints 



