3Qo ECONOMIC ZOOLOGY AND ENTOMOLOGY 



It is believed that the bot-flies of cattle, or the ox-warbles, 

 Hypoderma lineata, and H. bovis, gain an entrance into the ali- 

 mentary canal in the same way, that is by being licked from the 



FIG. 177. Bots, larvae of Gastrophilits eqiii, in stomach of horse. 



(Enlarged.) 



hairs on the body where the eggs have been laid by the adult 

 fly. But instead of passing on into the stomach they penetrate 



FIG. 178. Ox warble-fly, Hypoderma lineala. (About two and one-half 



times natural size.) 



the walls of the esophagus and later make their way through the 

 tissues of the body, until at last they reach a place along the 

 back just under the skin. Here, while completing their 



