48 DIPTEEA OF NORTH AMERICA. 



III. CORIACEA. 



F4M..LXII. HIPPOBOSCIDAE. 



Charact. Head flattened ; first joint of all the tarsi, or at least of the an- 

 terior and middle tarsi, abbreviated. 



N". A. possesses species of the genera HIPPOBOSCA Llnn\ MELO- 

 PHAGUS Latr., ORNITHOMYIA Leach, and OLFERSIA Wied., several 

 of which are perfectly identical with European species. 



FAM. LXIII. NYCTERIBIDAE. 



Charact. Head not flattened; first joint of all the tarsi rather long or 

 very long, in comparison with the following. 



One STREBLA only and a species belonging to a new genus are 

 known to me as occurring in N. A. 



