324 Annals Entomological Society of America [Vol. XI, 



g. Claspers with 4 or 5 large subequal teeth or spines. 



h. Distance from point on the costa opposite the base of Rg to 



the tip of Ri less than the distance from the tip of Ri to a 



point on the costa opposite the forking of the media. 



i. Costa extends at least one-half the distance between the tips 



of Rs and Mi. 



j. Clasper (Fig. 119) with one stout spine separate from the 



other 4 stout spines (Fig. 239). spinata n. sp. (sp. 24 Joh.) 



jj. Clasper with spines ecjuidistant (Fig. 114). Wing (Fig. 234). 



nacta Joh. 



ii. Costa extends less than one-half the distance between the tips 



of Rs and Mi (Fig. 50). Clasper has no separate stout spine 



(Fig. 19) 19. ovata n. sp. 



hh. Distance from point on the costa opposite the base of Rg to the 

 tip of Ri greater than the distance from the tip of Ri to a 

 point on the costa opposite the forking of the media. Wing 



(Fig. 233). Clasper (Fig. 113) mutiia Joh. 



gg. Claspers of different structure. 



h. Petiole of cubitus short, less than one-half as long as basal 

 section of M. 

 i. Rs ends distad of M2: costa produced about one-half of distance 

 from Rs to Mi. Mesonotum highly polished, 

 j. Halteres and coxae bright yeWovj .{ = nigricans Joh). 



johannseni End. 



jj. Halteres fuscous, (Figs. 217, 260) achwsa Joh. 



ii. Costa produced over one-half distance from Rg to Mi; if not, 

 then Rg ends proximad of tip of M2. 

 j. Clasper with 3 stout or several not stout apical teeth or 

 spines, 

 k. Clasper with about 3 stout apical spines. 



1. Distance from a point on the costa opposite the base of 

 Rs to the tip of Ri much less than the distance from 

 the tip of Ri to a point on the costa opposite the 

 forking of media. 

 m. Rg ends on the costa opposite a point on Mi proximad 

 of the midpoint of Mi. 

 n. Costa extends less than one-half the distance 

 between the tips of Rg and Mi (Fig. 267). 



ciicumeris Joh. 



nn. Costa extends a little more than one-half the 



distance between the tips of Rg and Mi (Fig. 241). 



fatigans Joh. 



mm. Rg ends on the costa opposite a point on Mi slightly 



distad of the midpoint of Mi. Costa extends less 



than one-half the distance between the tips of 



Rs and Mi (Fig. 51). Clasper (Fig. 20). 



20. trijurca n. sp. 



11. Distance from a point on the costa opposite the base of 



Rg to the tip of Ri slightly greater than the distance 



from the tip of Ri to a point on the costa opposite 



the forking of media (Fig. 52). Clasper (Fig. 21). 



21. pilata n. sp. 



kk. Clasper with more than three spines all of which are 



slender and not conspicuously distinguished from the 



setae of the clasper coprophila Lint. 



jj. Clasper without any or with only a single prominent apical 

 or subapical tooth, 

 k. Ri ends about opposite or only slightly proximad of the 

 forking of M. (Fig. 255). Knob of halteres and coxae 



brownish. Clasper (Fig. 115) varians Joh. var. c. 



kk. Ri ends considerably proximad of the forking of M. 



