184 INSECUTOR INSCITI^ MENSTRUUS 



the front. Palpi rather small, with four or five strong bristles 

 at tip. Mesonotum subshining, rather densely hairy ; scutellum 

 semicircular, with two strong bristles. Propleura with several 

 strong bristles next the coxa and several minute ones below 

 the spiracle ; mesopleura with an area of small bristles above 

 and one long backwardly directed one at the lower hind angle 

 of the area of small ones. Abdomen with some conspicuous 

 bristly hairs near the apex, continued on the lower half of the 

 sides and anterior ventral angles of the hypopygium ; apex 

 of hypopygium below with an asymmetrical hook-shaped 

 clasper originating on the left side, extending to the right 

 side and there curved forward. Anal organ short and stout, 

 densely hairy, its apical pair of bristles small. Legs slender ; 

 hind femora simple ; front tarsi thickened throughout, the 

 metatarsus as stout as the tibia ; setulas of posterior tibiae 

 minute, not developed at all on the basal half ; tibial spurs un- 

 usually weak. Costa slightly less than half the length of the 

 wing, its cilia short, especially on the basal half ; first section 

 about one-fourth longer than the second and third combined ; 

 second very little longer than the third ; costa apically and 

 third vein unusually thick, the cell at the furcation of the third 

 very small; fourth vein slightly curved throughout; fifth 

 nearly straight, strongly divergent from the fourth apically ; 

 seventh long, distinct ; all light veins very weak at apex, the 

 fourth and fifth also at the base ; wings broader than usual, 

 especially on the apical half. 



Female : Differs only in its smaller antennae, and in having 

 the first section of the costa a trifle longer and the wing some- 

 what narrower. 



Type male and paratype female from Moscow Mountain, 

 Idaho, June 17 (Melander). 



Similar to the European A. tarsalis Wood, which, however, 

 does not have the antennae enlarged in the male. 



Aphiochaeta scopalis, new species. 



Male. Length 2.0 mm. Deep black, legs beyond the coxae 

 piceous, the front pair more brown. Wings hyaline, heavy 



