24 U.S. NATIONAL MUSEUM BULLETIN 2 77 



5. Scenopinus cavifrons (Krober) 



Figure 6 (after Krober) 



Omphrale cavifrons Krober, 1937, p. 231. 



The type of this species has been destroyed. 



Length: Female body 4.1 mm., wing 3.7 mm. 



Type-locahty : JoinvUle, Algonquin, Canada? 



Holotype: (SMNH). 



A long series has been seen in the collection of the Illinois Natural 

 History survey with the label ''Algonquin" (Northern Illinois) which 

 may actually have been the source of Krober' s specimen. These 

 specimens all agreed with fenestralis (L.). However, since the type 

 cannot be checked, I have let the name stand. 



Figure 6. — Scenopinus cavifrons (Krober), female: 

 Details of frons and antenna (after Krober). 



6. Scenopinus efflatouni, new species 



Figure 7 



Female. — A moderately large robust fly typical of the group. Head 

 red-brown; eyes red-brown; postocular ridge moderately broad; frons 

 subshining with small pits for fine hairs, swollen on either side of a 

 median groove extending from the upper half to the median ocellus, 

 flat below; the ocellar tubercle slightly swollen, ocelli orange-brown. 

 First two antennal segments orange-brown; third segment three times 

 as long as the first two combined, red-brown. Mouthparts well de- 

 veloped. 



Thorax red-brown, with short recumbent white hairs, the posterior 

 margin of the humeral callus orange-brown; scutellum red-brown with 

 short erect white hair. Wings subhyaline, ^vith brown cast, veins 



