DESCRIPTION OF HORSEFLIES FROM MIDDLE 



AMERICA II.* 



James S. Hine. 



There has been notable progress in the study of Tabanidse- 

 in the last few years. Many new genera have been added and 

 some have been thrown into synonymy. Numerous generic 

 characters are available in the Pangoniuce, but this can hardly 

 be said of the Tabaninas. 



The material used for this paper is from various sources,, 

 but much of it is the property of the United States National 

 Museum and the American Museum of Natural History. 



PANGONIN^. 



The following key is offered as an aid in separating the genera of Pangoninat?- 

 of the region covered by the present paper only: 



1. Eyes distinctly hairy 2 



Eyes bare 6 



2. First posterior cell of the wing open Diatomineura 



First posterior cell of the wing closed 3 



3. Fourth posterior cell of the wing closed Scione 



Fourth posterior cell of the wing open 4 



4. Third antennal segment branched 5 



Third antennal segment not branched Erephopsis 



5. Third antennal segment branched both dorsally and ventrally. . . .Pityocera 

 Third antennal segment branched dorsally only Stichocera 



6. First posterior cell of the wing closed Pangonia 



First posterior cell of the wing open 7 



7. Third antennal segment composed of at least seven rings, the first of 



which is only slightly longer than the following ones 8 



Third antennal segment composed of five rings, the first of which is 

 much longer than the following ones 10' 



8. Eyes of the female acutely angulate above, wings of both sexes dark on 



the anterior part, hyaline behind Goniops 



Eyes of the female not acutely angulate above, wings nearly uniform in 

 color or hyaline 9' 



9. Front of the female wide, wider below than above, ocelli present, proboscis 



only a little longer than the palpi Apatolestes 



Front of the female of normal width or narrow, its sides usually parallel, 



proboscis often elongate Corizoneura 



10. Second segment of the antenna only half as long as the first Silvius 



Second segment of the antenna distinctly more than half as long as the 



first Chrysops 



*Conclusion of contribution No. 60, Department of Zoology and Entomology, 

 Ohio State University. 



311 



