42 PKOCEEDINGS OF THE NATIONAL MUSEUM vol. 8S 



Thorax and sciitellum black, gray pollinose; mesonotum marked 

 with four narrow bhick stripes, outer ones interrupted at suture and 

 stopping before base of scutelhnn; chaetotaxy as in valklinervls; 

 postscutelhim gra}- pollinose, pale membranous above; infrasquamal 

 hairs present; calypters tawnj^, paler at middle. 



Abdomen black, wholly covered with gray pollen; first segment 

 without median marginals; second with one pair; third and fourth 

 each with a marginal row ; no discals on anal segment ; genital seg- 

 ments reddish black retracted; fifth sternite prominent, narrowly 

 and deeply incised, the lobes pale yellow. 



Legs black, trochanters j'ellow, coxae less distinctly so; claws and 

 pulvilli shorter than the apical tarsal segment. 



Wings subhyaline; venation normal; third vein haired about half- 

 way to small cross vein; apical cell open a little before the exact 

 tip of wing; costal spine developed; epaulets red. 



Female. — Front at vertex 0.349 of the head width (one specimen) ; 

 fore tarsal segments compressed, the claws and pulvilli minute or 

 atrophied, otherwise very similar to male. 



Length. — 6 mm. 



Type.— Male, U.S.N.M. no. 19442. 



Remarks. — Redescribed from three specimens in the United States 

 National Museum. Two paratypes (male and female), Chosica, 

 Peru, May 25, 1913 (C. H. T. Townsend), and one male, Matucana, 

 Peru, April 22, 1914 (C. H. T. Townsend). 



There appear to be no characters of generic importance, common 

 to both sexes, that distinguish the species from Paradidyma. The 

 secondary sexual characters in the male, viz, the wide front and 

 presence of orbital bristles, at once separate it from all other known 

 forms. The female, however, agrees in the essential characters of 

 the present genus. As usual the front tarsi are compressed and 

 swollen, with the claws and pulvilli minute or atrophied. 



