346 



NORTH AMERICAN DIPTERA. 





Fig 141. CEstridae. I, Gastrophilus, wing; 2, Gastrophilus, anten- 

 nae; 3, Cuterebya, antennas; 4, Cuterebra, front tarsus; 5, Cuterebra, 



wing, 



/ " * 



; 6, Dermatobia, wing; 7, Dennntobia, front tarsus. 



TABLES OF GENERA. 



IMAGINES. 



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

 Proboscis genicnlate, 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wing, i. e. the apical cross-vein is obsolete, and the first poste- 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 (1, 2). 



Gastrophilus. 



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 or depression. ........ 4 



