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MISC. PUBLICATION 6 31, U. S. DEPT. OF AGRICULTURE 



tain characters of the male. Since the keys given here are based 

 partly on male characters, they can be used for the females only 

 with great limitations ; and they are not altogether satisfactory even 

 for the males. Final determinations must, in many cases, depend on 

 an examination of the male terminalia. It must also be kept in mind 

 that only a small part of this great genus is being treated in this work. 

 Positive identifications in this genus require the specialist ; it is hoped, 

 however, that the discussion here will give some indication as to what 

 the species in hand may be or, at least, what it is not. 



KEY TO NEW WORLD SPECIES (BASED LARGELY ON MALES) 



1. Three postsutural dorsocentrals, more or less evenly spaced (cf. 



Titanogryplia alata, fig. 12, B). Sarcophaga sarraceniae, as well as 

 many other species which are not known to have any connection with 

 myiasis, will trace here ; see also S. lambens, in which an occasional 

 aberrant specimen may have the first postsutural dorsocentral poorly 

 developed. 

 Four or more postsutural dorsocentrals (fig. 12, A), of which all but 

 the last two may be weak 2 



2. Flexor surface of hind femur in the male with strong spinelike bristles ; 



male hypopygium large and robust (fig. 20) plinthopyga Wiedemann 



Flexor surface of hind femur in the male with at most ordinary bristles. 3 



Figure 16. — Sarcophaga oullata, hind leg of male. 



3. Hind tibia of the male with only ordinary hairs 4 



Hind tibia of the male with long villous hairs forming at least a partial 

 fringe (fig. 16) 7 



Rows of frontals diverging below (fig. 18) ; epaulet black, though the 

 basicostal scale is yellow 5 



Figure 17. — Sarcophaga striata, head of female, front view. 



