110 J.NSECUTOR INSCITI^ MENSTRUUS 



blackish. Mesonotum rather dark brown, on the disk dusted 

 with gray and with three indistinct brown longitudinal lines ; 

 humeri and lateral margins creamy yellow ; scutellum brown ; 

 vestiture of rather sparse, long, pale yellow hairs; pleurae 

 blackish, some of the sutures broadly pale margined ; postnotum 

 black. Abdomen elongate, depressed, nearly straight-sided, the 

 fifth, sixth, and seventh segments distally broadened; color 

 dull black, with narrow whitish bands at the bases of the 

 segments ; vestiture of short pale hairs and scattered long 

 whitish hairs laterally and distally. Wings smoky gray, clothed 

 with dark brown hairs, the extreme base and a small spot 

 on the costa before apex of first vein whitish ; costa clothed 

 with dense black hairs to wing-tip ; first vein ending in the 

 costa slightly before middle of wing. Halteres dull black. 

 Coxae yellowish ; legs yellowish, the anterior pair without pro- 

 nounced infuscations and with the first tarsal joint about two- 

 fifths the length of the second; middle and hind legs with the 

 apices of the femora and the bases of the tibiae broadly black- 

 ened; hind tarsi with the first joint hardly more than half as 

 long as the second; all the tarsi somewhat infuscated; all the 

 legs clothed rather densely with short and moderately long 

 pale hairs, some very long scattered ones on the tibiae and hind 

 tarsi. Claws long and slender. Length : Body about 2 mm., 

 wing 2 mm. 



Male. Differs from the female in the usual sexual char- 

 acters. The mesonotum shows a more pronounced pruinose 

 median zone, bounded by more distinct dark stripes at lateral 

 thirds ; hairs shorter and finer. Scutellum with a fringelike 

 row of very long pale yellowish hairs. Abdomen long, narrow, 

 the second, third, and fourth segments with very broad whitish 

 apical bands, the succeeding segments wholly black. Legs 

 longer and more slender than in the female and with much 

 more numerous very long hairs, almost forming a fringe on 

 the hind tibiae. Wings much narrower than in the female. 

 Length : Body about 2.5 mm., wing 2 mm. 



Matucana, Peru, 1 female, 1 male, April 22, 1914 (C. H. T. 

 Townsend) . 



Type, Cat. No. 19955, U. S. Nat. Mus. 



