602 DIPTEEA. 



swelling which last several days. These little tormentors 

 are of a black color ; their wings are transparent ; and their 

 legs are short, and have a broad whitish ring around them. 

 The length of their body rarely exceeds one tenth of an inch. 

 They begin to appear in May, and continue about six weeks, 

 after which they are no more seen. They are followed, 

 however, by swarms of midges, or sand-flies (Simulium 

 nocivum), called no-see-'em, by the Indians of Maine, on 

 account of their minuteness. So small are they, that they 

 would hardly be perceived, were it not for their wings, 

 which are of a whitish color, mottled with black. Towards 

 evening these winged atoms come forth, and creep under 

 the clothes of the inhabitants, and by their bites produce 

 an intolerable irritation, and a momentary smarting, com- 

 pared * to that caused by sparks of fire. They do not draw- 

 blood, and no swelling follows their attacks. They are most 

 troublesome during the months of July and August. 



The most common of our large gad-flies, or horse-flies, 

 appears to be the Tabanus atratus of Fabricius. It is of 

 a black color, and the back is covered with a whitish bloom, 

 like a plum. The eyes are very large, and almost meet 

 on the top of the head ; they are of a shining purple-black 

 or bronzed black color, with a narrow jet-black band across 

 the middle, and a broad band of the same hue on the lower 



part. The body of this fly is 



Flg ' 26L seven eighths of an inch or more 



in length, and the wings expand 



nearly two inches. The Tabanus 



ductus (Fig. 261) of Fabricius, 



or orange-belted horse-fly, is not 



so common and is rather smaller. 



It is also black, except the first 



three rings of the hind body, which are orange-colored. 



The most common of our smaller horse-flies is the Tabanus 



lineola (Fig. 262), so named by Fabricius, because it has 



* See Gosse's Canadian Naturalist, p. 100. 



