346 



NORTH AMERICAN DIPTERA. 



Fiji M 1 - CEstridae. i, Gastrophilus, wing; 2. Gastrophi/us, anten- 

 nae; 3, Culerebra, antennae; 4, Cuterebra, front tarsus; 5, Cuterebra, 

 wing; 6, Dertnatobia t wing; 7, Dermaiobia, front tarsus. 



TABLES OF C-ENERA. 



IMAGINES. 



1. Mouth-parts very small, vestigial; arista bare. ... 2 

 Proboscis geniculate, inserted in a deep slit; female without extri- 

 cate ovipositor; first posterior cell narrowed or closed; arista 

 bare or plumose; facial grooves approximated below, enclosing 

 a narrow median groove or depressed surface; squamae large. 6 



2. The fourth longitudinal vein runs straight toward the border of the 



wing, i. e. the apical cross-vein is obsolete, and the first poste- 

 rior cell is not narrowed; squamae small: female ovipositor elon- 

 gate; larvae in stomach and intestinal canal il, 2). 



G-astrophilus. 



The fourth vein turns forward to form the apical cross-vein, closing 



or narrowing the first posterior cell. ...... 3 



3. Facial grooves approximated below, leaving a narrow median 



groove <>r depression. ........ 4 



