46 OHIO state; academy of scienck. 



GONioPS CHRYSOCOMA Osten Sacken. 



Length 12-14 mm. Abdomen short and wide ; legs pale ; wings 

 hyaline at base and on pai't of posterior margin, otherwise dark almost, 

 black in fully matured specimens. 



Female : Body entirely pale yellowish although some specimens, 

 show a brownish tinge on dorsum of thorax and abdomen, posterior 

 margins of abdominal segments clothed with silvery white hair ; face 

 and front wide, eyes small, and pointed above, a line along the inner side 

 of each from the most inferior to the most superior points is very nearly 

 a straight line; proboscis much shorter than the head, palpi nearly as- 

 long as the proboscis. 



Male: Thorax black above with two narrow longitudinal stripes, 

 abdomen black with a tinge of reddish on the sides and with narrow 

 posterior margins to the segments ; clothed with pale yellowish pile. 



Habitat : Northern and Southern Ohio. 



I have taken both sexes of this species from foHage, but have- 

 not observed the female around stock. The pecuhar dark mark- 

 ings on the wings of both sexes and the form of the eyes and 

 wide front in the female will serve to distinguish this species 

 from all others of the family in our fuana. 



TABANus Linne. 

 Fauna Suecica, 1761. 

 In this genus the markings of the abdomen are niuch used' 

 for distinguishing species. The term gray markings as used in 

 the key below refer to the rows of triangles and to the stripes, 

 and not to the gray margins of the various segments. The males, 

 and females of the same species in this genus are very much 

 alike in coloration, so it does not appear necessary to construct 

 a separate key for each sex. 



Key to the species. 



1. Eyes bare "2.. 

 Eyes pilose 16.. 



2. Abdomen with definite gray markings 3. 

 Abdomen not with definite gray markings 13.. 



3. The gray markings of the abdomen consist of a single longi- 



tudinal row of triangles 4- 



The gray markings of the abdomen consist of three longi- 

 tudinal rows of triangles or spots 9.. 

 The gray markings consist of a middorsal stripe running from 

 the scutellum to the end of the abdomen, and usually an 

 additional stripe on each side 12. 



4. Wing uniformly hyaline, but the stigma brown coffeatus. 

 Wing smoky on basal part or with' distinct spots of brown, at 



least along the cross veins and bifurcation of the third veiii 5. . 



5. Wing with distinct brown patches other than along the cross 



veins and the bifurcation of the third vein venustus. 



Wing without distinct brown except along the margins of the 



cross veins and bifurcation of the third vein G- 



