20 DIPTERA OP NORTH AMERICA. 



with the genera separated from it and partly connected with each 

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

 rhynchus Macq., Gadicera Macq., Nuceria Walk., Melpia Walk., 

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

 Walk., Scione Walk., Plinthina Walk., Scarphia Walk., and Lilcea 

 Walk.; moreover, the genera: SCEPSIS Walk., SILVIUS Meig. , ME- 

 SOMYIA Macq., TABANOCELLA Big., ECTENOPSIS Macq., RHINOMYZA 

 Wied., ERODIORHTNCHUS Macq., GASTROXIDES Saund., PRONOPES 

 Loew, CHRYSOPS Meig., and NEMORIUS Rond. 



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

 rioplectes Zell., DICHELACERA Macq., LEPISELAGA Macq., SELA- 

 SOMA Macq., HADRUS Pert., DIABASIS Macq., ACANTHOCERA Macq., 

 DASYBASIS Macq., HEXATOMA Meig., and H^MATOPOTA 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. t 6. DIABASIS Macq., 7. H.EMATOPOTA 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. Tibije with 

 spurs ; empodium much developed, pulvilliform. 



This family is very easily distinguished from the foregoing 

 families by the simple third joint of its antenna. 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 Fair., YERMILEO Macq. (= 

 Psammorycter Blanch.), ATHERIX Meig., NODUTIS Meg. (= Ibisia 

 Rond.), and SPANIA Meig. (= Ptiolina Zett. = Leptipalpus 

 Rond.). 



The 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. 



