241 



black, hut when viewed from l)ehind the sparse whitish pollinosity 

 obscures the surface of each segment so as to leave a narrow dorso- 

 central stripe and a narrow post-marginal fascia ; hypopygium black, 

 the surface grayish pollinose. Legs black, fore tibia and all the tarsi 

 yellowish. Wings clear. Calyptr.ne white, the fringe concolorous. 

 Halteres yellow. 



Frontal stripe very wide, at vertex one fourth the width of the 

 head, becoming slightly wider near to base of antennae ; orbits wide, 

 each at middle equal to width of central stripe; one distinct orbital 

 bristle present ; inner margin of orbits with a single row of rather 

 strong cruciate setuUx, otherwise bare; antennae reaching to epistome, 

 third joint broader than usual in this genus; arista bare; palpi normal. 

 Mesonotum with two presutural macrochaetae ; the acrostichals in 

 three rows. Abdomen not longer than thorax; hypopygium distinct, 

 though not conspicuous. Fore tibia with only the preapical bristle; 

 mid and hind femora slightly thickened, the former very little con- 

 stricted at apex ; antero-ventral surface of mid femur with rather 

 short bristles, which are somewhat widely spaced to middle (4—5), 

 then become closer, and on the apical third become \ery short and 

 comblike; postero-ventral row rather longer; mid tibia becoming 

 slightly thicker from base to apex, the pubescence on the ventral 

 surface very short and inconspicuous ; the usual bristles present on 

 the apical third, but very weak; hind femur with a row of very weak, 

 short, hairlike bristles on the antero-ventral surface, only the last two 

 strong, the postero-ventral surface without any distinct bristles; hind 

 tibia with tw^o dorsal, one antero-dorsal, and one antero-ventral 

 bristles; no distinguishable setulae above the antero-dorsal bristle; 

 tarsi normal. Outer cross vein of wing at about its own length from 

 end of fifth vein; last section of fourth vein about two and one half 

 times as long as the penultimate section. Under scale of calyptrae 

 distinctly larger than the upper. 



Length, 2.5 mm. 



Locality, Elliott, Illinois, July 10, 1906 (E. O. G. Kelly). 



This species is readily separated from any previously described 

 form in this genus by the very widely separated eyes. In general 

 appearance latifrons resembles Stcmomyia steini Malloch, but the 

 lower orbital bristle of the male of the former is not present in 

 latifrons. 



In the same collection there is a female in rather poor condition 

 that very probably belongs to this species. It differs from the male 

 in having the frons with white pollinosity, which is not silky, or 

 metallic in luster; in having the normal 2 orbital bristles; only 3 



