2i8 
The Ohio Naturalist. 
[Vol. V, No. 2, 
later it has been possible to get together a large and representa- 
tive collection from the region covered by this paper. Through 
correspondence with Miss Gertrude Ricardo who has studied 
Bigot’s types and also the Tabanidae of the British Museum I 
have gained much. She has even redescribed several of Bigot’s 
types for me and by this means I have satisfactorily identified a 
number of his species. 
The European material I have for comparison consists of a 
large number of species acquired by exchange with Prof. Morio 
Bezzi of Italy, Dr. K. Kertesz of the Hungarian National Museum 
and E. Brunetti of England. In comparing one is convinced, 
with Dr. Loew, that hardly any of the species of the two countries 
seem to be exactly the same but in some cases they are very close. 
Since I have been studying this family I have visited The 
Museum of Camparative Zoolbgy, The U. S. National Museum 
and The Museums of Kansas University and The University of 
Illinois. At each place I was given every opportunity to study 
the contained material and am under obligations for these 
privileges. 
In most cases under each species only those characters of 
most consequence in determination are mentioned. 
Key to the North American Genera. 
1. Hind tibiic with spurs at the tip 2 
Hind tibiae without spurs G 
2. Third segment of the antenna composed of eight annuli the first 
of which is only a little longer than the following ones 3 
Third segment of the antenna composed of only five annuli the 
first of which is much longer than the following ones; ocelli 
present 5 
3. Front of female narrow ; ocelli present or absent ; fourth posterior 
cell at least open Pangonia* 
Front of female broad with a denuded callus; ocelli present 4 
4 Eyes in the female acutely angulated above; wing in both sexes 
with a dark picture Goniops 
Eyes in the female not acutely angulated above; wings hya- 
line -d patolcstcs 
5. .Second segment of the antenna about half as long as the first ; 
eyes in life with numerous small dots Silviiis 
Second segment of the antenna as long or but little shorter than 
the first; wing with a dark picture Chrysops 
G. Third segment of the antenna with a well developed basal 
process Tabanusf 
Third segment of the antenna without, or with a rudimentary 
basal process 7 
7. All the tibi:e enlarged, the hind pair ciliate Snowiellus 
None of the tibiae enlarged and the hind pair not ciliate 8 
8. Front of the female as broad as long the callus transverse Hcematopota 
Front of the female narrow Diachlorus 
* Including Diatomincura and Corizoneura. 
t Including Atylotus and Therioplectes. 
