20 DIPTERA OF NORTH AMERICA. 



with tbe genera separated from it and partly connected with each 

 other by passages: Philoliche Hffgg., Dicrania Macq., Peleco- 

 rhynchus Macq., Cadicera Macq., Nuceria Walk., Melpia Walk., 

 Scaptia Walk., Tacina Walk., Phara Walk., Clanis Walk., Osca 

 Walk., Scione Walk., PUnthina Walk., Scarphia Walk., and Lilcea 

 Walk.; moreover, the genera: Scepsis Walk., Silvius Meig. , Me- 

 somyia Macq., Tabanocella Big., Ectenopsis Macq., Rhinomyza 

 Wied., Erodiorhynchus Macq., Gastroxides Saund., Pronopes 

 Loew, Chrysops Meig., and Nemorius Pond. 



The Tabanina comprise the genera: Tabanus Linn., with The- 

 rioplectes Zell., Dichelacera Macq., Lepiselaga Macq., Sela- 

 soma Macq., Havrus Pert., Diabasis^/Wc^., Acanthocera Macq., 

 Dasybasis Macq., Hexatoma Meig., and Hjematopota Meig. 



The N. A. species which we are acquainted with belong to the 

 genera: I. Pangonina: 1. Pangonia Latr., 2. Silvius Meig., 3. 

 Chrysops Meig. II. Tabanina: 4. Tabanus Linn., 5. Lepi- 

 selaga Macq., 6. Diabasis Macq., 1. ILematopota Meig. 



Fam. XY. LEPTIDAE. 



Charact. — Three basal cells much prolonged ; third longitudinal vein fur- 

 cate ; two intercalary veins always present ; marginal vein running 

 round the whole border of the wing. Third joint of the antennae 

 simple, with a simple or thickened styliform bristle. Tibiae with 

 spurs ; empodium much developed, pulvilliforni. 



This family is very easily distinguished from the foregoing 

 families by the simple third joint of its antennas. A division into 

 sections has not been attempted yet, and would be useless for the 

 small number of genera hitherto known. The genera belonging 

 to this family are as follows: Dasyomma Macq., Chrysopila 

 Macq. % Triptotricha Loew, Leptis Fabr., Yermileo Macq. (= 

 Psammorycter Blanch.), Atherix Meig., Nodutis Meg. (= Lbisia 

 Rond.), and Spania Meig. (= Ptiolina Zett. = Leptipcdpus 

 Rond.). 



Tbe location here of the genus Syneches is one of the many 

 errors which we meet with in the writings of Mr. Walker. 



I know N. A. species belonging to the genera : 1. Chrysopila 

 Macq., 2. Leptis Fabr., 3. Triptotricha Loew, 4. Atherix Meig. 

 Mr. Walker has also recorded a species of the genus Spania Meig. 



