152 XOETH AMERICAN DIPTERA. 



STREBLIN^. 

 1. Eyes small, situated on the posterior angles of the head. 



Strebla Wiedemann. 

 Eyes situated near the middle of the head (Mexico). 



Trichobius Townsend. 



HIPPOBOSCIN.^. 

 1. Claws tridentate. .......... 2 



Claws bidentate. .......... 3 



2. Wings rudimentary ; ocelli wanting. Bkachypteromtia Williston. 

 Wings large, functional; ocelli present. Ornithomyia Latreille. 



3. Wings wanting or rudimentary, in the males at least. ... 4 

 Wings present, functional, 5 



4. Eyes very narrow and situated on the sides of the head ; no ocelli. 



Melophagus Latreille. 

 Eyes larger, oval; ocelli present, but sometimes indistinct; wings ca- 

 ducous in one or both sexes. . - . Lipoptexa Nitsch. 



5. Antennfe short, tuberculiform. . . . Hippobosca Linne. 

 Antenna? elongate, clothed with hair distally. . < )lfersia Leach. 



59. ?^YCTERIBI/D/E. 



Head small, capable of being turned backward into a groove 

 on the dorsum of the thorax. Anteniue sliort, indistinctly 

 jointed, the terininal joint oval, with short hairs. Eyes and 

 ocelli indistinct or wanting. Legs long, the femora and tibia 

 flattened. Tarsi arcuate. No wings. 



Tiiese peculiar flies, like tliose of the foregoing family, are 

 pupiparous. They live exclusively on bats. But little is 

 known of their early stages. (See Osten Sacken.) The flies 

 have a peculiar, s})ider-like appearance, which is heightened 

 by the habit they have of throwing their legs up over their 

 back when at rest. But two or three species are known from 

 North AmtM-ica, and tliey are rare. I have never seen them. 



TABLE OF GENERA. 

 L Metatarsi elongate. ..... XvrTKiiiniA Westwood. 



Metatarsi short. ...... Mkcistopoda Muctjiiart. 



