454 



THE STUDY OF INSECTS, 



In this family the third segment of the antenna is ringed 

 (Figs. 537, 538) and is never furnished with a distinct style 



or bristle. The wing-veins (Fig. 539) 

 are evenly distributed over the wing, 

 as the branches of vein III are not 

 crowded together as in the follow- 

 ing family ; the costal vein extends 

 completely around the wing ; the 

 alulets are large. 



The flight of these flies is very 

 powerful ; they are able to outstrip 

 the swiftest horse. The males feed 

 on the nectar of flowers and on 



Fig. 538. 



Antenna of swcct sap. Tlic moutli-oarts of the 



Chrysops. 



female are fitted for piercing the 

 skin and sucking the blood of men and quadrupeds; the 



Fig. 537. 

 Antenna of 

 Tabanus. 



^Vlla + IX' VHi: ^^ 

 Fig. 539. — Wing^ of Tabanus. 



females, however, also feed on the sweets of plants v/hen 

 they cannot obtain blood. 



The larvae are carnivorous ; many live in the earth ; others 

 live in water. They feed on various small animals ; some 

 upon snails, others upon the larvae of insects. In most cases 

 they have a single pair of spiracles, which is situated at the 

 hind end of the body; some have a pair of spiracles at 

 each end of the body. The pupa is not enclosed in the 

 skin of the larva. 



