LV. Family CESTRID^E. 



Fig. 140. Cuterebra buccata, enlarged; after Washburn. 



Flies of moderate to large size, thick-set, usually more 

 or less pilose. Head large, the lower part more or less 

 swollen. Antennae short, three-jointed, decumbent, and 

 more or less sunken in the facial groove or grooves; 

 arista bare or plumose. Mouth opening small, the 

 mouth-parts sometimes rudimentary, never large. Front 

 broad in both sexes, in the male broader in front. Eyes 

 comparatively small, bare. Ocelli present. Thorax ro- 

 bust, with a distinct transverse suture. Abdomen short, 

 conical or but little elongated; genitalia of the male hid- 

 den, the ovipositor sometimes elongated. Squamae usu- 

 ally large; sometimes small. Venation of the wings 

 muscid-like, in most cases the first posterior cell narrow- 

 ed or closed; anal cell small, sometimes indistinct; discal 

 cell sometimes absent. 



This family, though of small size comparatively, is of 

 the greatest fnterest by reason of the habits of the larvae, 

 all of which that are known being parasitic upon mam- 

 mals. The adult flies often have vestigial mouth-parts, 



344 



