234 



PARASITIC DISEASES 



depositing the egg. The color of the egg is yellow, and it 

 adheres firmly to the hair. It hatches in from two to four 

 weeks, and the larva reaches the mouth through the animal lick- 

 ing the part. From the mouth, it passes to the stomach, where 

 it attaches itself to the gastric mucous membrane (Fig. 62). 

 Here it remains until fully developed, when it becomes detached 

 and is passed out with the ftijces. The third stage is passed in the 



FiQ. 62. — A piece of the wall of the horse's stomach showing the bot-fly larvse attached. 



ground. This takes place in the spring and early summer 

 and lasts for several weeks, when it finally emerges a mature fly. 

 The hot-fly of the ox (11. lineata) is dark in color and about 

 the size of a honey-bee. On warm days, the female may be seen 

 depositing eggs on the body of the animal, especially in the 

 region of the heels. This seems to greatly annoy the animal, 

 and it is not uncommon for cattle to become stampeded. The 



