182 ORDER DIPTERA. 



Neither of the foregoing species are figured or described in Say's American Entomology, 

 but there is very little doubt that they belong to the Genus Leptida. The flies are found 

 in thickets in the summer : they feed on other small insects, and their larvse live in offal 

 or on decaying wood. 



Tabaiiidae. 



Tabanps pldmbeus ( Linnaeus). Gad-fly. Horsefly. 

 Tabancs plumbeus ( Drury). T. ruficornis ( Fabricias). T. limbatus ( Pal. de Beauvois). 



* Head ash-colored ; eyes black ; antennae reddish brown ; ocellus one ; thorax greenish, 

 ' with a white spot at the base of each wing ; abdomen dai-k brown, each segment of 

 ' wliich on the underside is margined with gray ; wings transparent, anterior edges 

 < brown and opake ; legs dark brown, the middle ones being armed with two spines 

 <■ at the tip of each tibia : the ungues have two small brown scales under them. 

 ' Breast hairy ; back colored, but white on the sides ' ( Westwood, Illustrations of 

 Drury, Vol. 1, p. 97). 

 This species appears in New- York In July, and is most common in woody places, but is 

 often in open pastures, and frequents roadsides, alighting on horses and cattle. In New- 

 York and New-England they are too few in number to occasion much trouble, though 

 their probosces are armed with lancets sufficiently long and sharp to wound cattle severe- 

 ly. Were they as numerous as the smaller kinds of flies, our pastures could not be occupied 

 during the months of July and August. 



Tab ANUS americancs ( Drury). 



Tabanus ateatus ( Fabricius). T. nigee ( Pal. de Beauvois). 



Head, antennse, sheath of the proboscis, extremity of the abdomen, breast and legs black j 

 thorax brownish black ; wings dark brownish, scarcely opake ; anterior part of the 

 abdomen dark plumbeous ; spines of the middle legs two ; breast hairy. 



The lighter part of the abdomen appears as if covered with a whitish bloom. The eyes 

 are very large, and meet at their lower edges, but are separated above by a narrow yel- 

 lowish space : their color is black and bronzed. Length seven-eighths of an inch, or 

 nearly one inch ; expansion of wings, nearly two inches. 



This species is rather smaller than the plumbeus, with wings less robust and strong : it 

 appears at the same time, and attacks cattle and horses in the same savage way. Both are 

 found as far south as Maryland. 



