Dec, 1904.] Tabanidae. 235 



Tabanus benedictus Whitney. A large species related to 

 nigrescens of the eastern states. The first posterior cell of the 

 wing is closed, or nearly closed. The front is rather narrow, 

 narrowest anteriorly, the frontal callosity before almost as wide 

 as the front, gradually narrowed, about twice as long as wide, 

 and connected behind with a narrow line which extends to near 

 the last third of the front. Abdomen dark brown, pruinose, 

 resembling the abdomen of the common atratus. Length nearly 

 25 millimeters. Specimens from Louisiana. The types were 

 taken in Missouri. 



It is not properly a western species in the sense of this paper, 

 but is included because it has been described only recently, and 

 therefore is not mentioned in papers treating eastern species. 



Tabanus captonis Marten. In his bibliography of North 

 American Dipterology Dr. Williston has omitted Marten's paper 

 entitled "New Tabanidae" in the Canadian Entomologist XI, 

 210, and in his paper ' 'Notes and Descriptions of North American 

 Tabanidae" published in Trans. Kan. Acad, of Sci. he did not 

 mention the four species described therein, although he men- 

 tions all the species described in Marten's other paper. It would 

 appear that the first paper was omitted through oversight. At 

 any rate, I believe that Williston's comastes is synonymous with 

 Marten's captonis. The species has somewhat the aspect of 

 affinis, but the female is easily known by its very wide front, grad- 

 ually narrowed anteriorly, and the denuded subcallus. 



The male is like the female. The antennae are red with the 

 exception of the apical portion of the third segment which is more 

 or less black, the frontal triangle is covered with silvery white 

 pollen. 



Tabanus centron Marten. As stated under rhombicus I con- 

 sider this equivalent to Osten Sacken's second form of rhombicus. 

 The subcallus is denuded, the antennae are black with base of 

 third segment red, and in some specimens the two basal segments 

 are reddish with short black hairs. There is no stump at the base 

 of the anterior branch of the third vein, and the wings are hyaline 

 with costal cell yellowish and faint clouds on the margins of the 

 cross-veins and furcation of the third vein. In some specimens 

 the abdomen is reddish on the sides of the first three or four seg- 

 ments. The male is colored like the female. Length 16 to 17 

 millimeters. 



' Tabanus coffeatus Macquart. A dark colored species measur- 

 ing 12 to 13 millimeters in length. Taken in many of the eastern 

 states and as far west as Colorado. Each abdominal segment is 

 black with a white posterior border which expands into a prom- 

 inent triangle on the middle of the dorsum. Very distinct from 

 all western species but much like small specimens of melanocerus 

 from the eastern states. 



