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 sweet sap. The mouth-parts of the 



Lhrysflps. 



female are fitted for piercing the 

 skin and sucking the blood of men and quadrupeds; the 



FIG. 537 



Antenna of 



Tabanus. 



Vllt 

 FIG. 5^0 Winer of Tetanus. 



females, however, also feed on the sweets of plants when 

 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. 



