56 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 6n. 



gray pollen dense on the basal portion of the segments, divided 

 b}' a ratlier distinct narrow median line on the second and third 

 segments and partially divided on each side of this by a prolonga- 

 tion forward of the more shining posterior margin; fourth segment 

 with dense pollen which is merely notched a little behind in the 

 middle; first and second segments each with a single smallish pair 

 of marginals; third segment with a row^ of eight; fourth segment 

 with two discal bristles back of the middle and a marginal row 

 which passes into a cluster below on each side of the genitalia; the 

 two genital segments are reddish-brown without distinct bristles; 

 the inner forceps are united into a somewhat conical, long, black, 

 hook-like organ distinctly hairy on the sides and behind, resembling 

 the one found in Tachinomyia rohusta. The outer forceps are modi- 

 fied into flat yellow^ish plates with rounded hairy, blackish tips. The 

 fifth sternite is deeply cleft, but bears only a few small hairs on the 

 outer side of the lobes. Legs black, the middle tibiae with two or 

 more long bristles on the front side ; all the claws and pulvilli much 

 elongated. Wings subhyaline, narrow at tip; hind cross- vein ob- 

 lique ; bend of fourth vein rectangular and with a very distinct fold 

 but not a continuation of a vein; first posterior cell ending far be- 

 fore the apex. Third vein with several bristles at the base, extend- 

 ing about half way to the small ci-oss vein. 



Female— 'W\^i\\ of front 0.34 of head width (two specimens 0.35 

 and 0.325). Abdomen with hardly any trace of a median stripe, 

 the hind edges of segments 2, 3, and 4, shining black. The fourth 

 segment with numerous spiny bristles especially below. 



Length of male, 6 to 13 mm. ; of female, 5 to 9.5 mm. Both sexes 

 normally approximate the maximum of these figures, the smaller 

 specimens having been reared in cages with insufficient food. 



Type. — Male, from Las Cruces, New Mexico, deposited in tlie 

 University of Kansas; examined by the senior author. 



Other material examined: Type (Cat. No. 15141) and 7 other 

 specimens of peruviana., from Peru (Townsend) ; type (Cat. No. 

 15142) and 2 other females of minor., from Peru (Townsend) ; more 

 than 50 specimens from Tempe, Ariz., reared from Malacosoma 

 americanuin Fabricius, many dwarfed (Caff rev) ; 3 from Texas, 

 collector unknown; 1 Rio Urique, Chihuahua, Mexico (Townsend). 



In its more northern distribution this species overlaps claripennis, 

 from which it is readily distinguished in the male by the tufts of 

 bristles in front of the middle coxae. This character occurs in a 

 series of southern forms, however, and reference to the male genitalia 

 is necessary to separate these readily. The elongation of the abdomen 

 in the male, also occurring in several species, is best developed in 

 the largest specimens, and becomes practically imperceptible in the 

 small ones. 



