662 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



Eggs of the common bot fly are small, oval, yellow objects com- 

 monly called nits, and attached to hairs on the fore-quarters of the 

 horse. The horse licks them off and they hatch in the mouth, 

 making their way into the stomach. Here they live some months, 

 passing out with the excrement in the spring or early summer and 

 pupating in the soil. Injury is due to malnutrition and to the 

 irritation of the tissues of the stomach. 



The throat-bot differs in its habits in some details from the 

 common bot-fly. It generally lays its eggs just under the chin or 



FIG. 581. Bots attached to the wall of the stomach of a horse. (After 

 Osborn, U. S. Dept. of Agr.) 



jaws. The larvae of this species sometimes attach themselves in 

 the pharynx where they may seriously interfere with taking food 

 or even with the breathing. They attach also in the stomach but 

 are most frequently found in the duodenum where they may be 

 so numerous as to interfere with the passage of the excreta, in 

 which case serious consequences ensue. 



The nose-fly attaches its eggs usually on hairs on the lips and 

 it causes much more excitement to the animal in the process than 

 do the other species. Apparently the egg-laying in this situation 

 is attended by some pain to the animal. The larvae attach in the 

 stomach or duodenum and later, when nearly or quite grown 

 reattach themselves in the rectum or anus, causing acute discom- 

 fort to the animal and interfering with the passage of the excreta. 



