ARTHROPODA 



the horse licks himself the eggs get into his alimentary canal where 

 they hatch into maggot-like larvae. 



The bot-fly larvae of cattle, the ox warbles, get into the alimentary 

 canal in the same way, but instead of lodging in the stomach they bur- 



FIG. 70. Wing of stable-fly, Stomoxys calcitrans. 



Disease.) 



(After Doane, Insects and 



row out through the esophagus until they come to lie under the skin 

 of the back; here they develop and make ugly sores, and when mature 

 they cut through the skin, fall to the ground and complete their develop- 



PIG. 71. Wing of house-fly, showing adhering dirt in which bacteria may lodge. 

 (After Doane, Insects and Disease.) 



ment. The holes they make in escaping injure or even ruin the skin for 

 leather. 



The human bot or screw-worm flies lay their eggs in sores on the 

 body; the eggs very quickly hatch and the maggots burrow under the 

 skin causing painful and even fatal results. 



