477 



Family Streblidae— The Bat Flies 



Pterellipsis aranea. 



Head of moderate size, with a freely movable neck. Eyes, when 

 present, small, without or with very few facets; ocelli absent. Antennae 

 inserted in a pit, two segmented, the second segment with a bristle. 

 Proboscis short, not protrusible, thickened basally; palpi broader than 

 long, projecting leaf-like in front of the head, not forming a sheath 

 for the proboscis. Abdomen with a distinct basal segment, the other 

 segments rarely distinguishable, the basal segment with special bristles 

 for the protection of the wings when at rest. Posterior coxfe always 

 enlarged; fifth segment of the tarsi usually elongate and enlarged; pul- 

 villi present, the claws never toothed. Wings sometimes vestigial or 

 wanting, when present the veins stout and covered with hairs. Halteres 

 present.- 



All but one species are parasitic upon bats but they are restricted 

 to the tropics and the subtropico-temperate zones. Kessel* has reviewed 

 the family. 



KEY TO GENERA f 



1. With a ctenidium of black bri.^tles on the ventral surface of the head . . 2 

 Without a ctenidium on under surface of head 4 



2. Eyes present; wings well-developed, with six veins (1) 3 



Eyes absent; wings reduced to oval pads, much shorter than the thorax. 



Metelasmus Coquillett 



* 1925. Journ. N. Y. Ent. Soc. xxxiii, pp. 11-34, 4 plates. 

 t Checked by Dr. J. Bequaert. 



