218 



BOT-FLIES. 



that the presence of such bots had a beneficial influence upon- 

 the digestive functions. The larva;, when mature, are of a 

 light-yellow color, with spines white at base and dark-brown 

 at the tip. They are distinguished from the other bot-fly 

 larvae by having only one row of spines at the anterior bor- 

 der of their segments, of which the tenth one is unarmed- 



Fig. 179. — Nasal bot-fly. Greatly enlarged. Original. 



They are found only in the pyloric regions of the duodenum,, 

 and they do not fix themselves to the margin of the anus be- 

 fore being evacuated. 



If but few bots occur in the host they are harmless, but 

 if very numerous they assuredly cause some pains, and in 

 very extreme cases even colic; and where they penetrate 

 through the mucous membrane into the body cavity, they 

 cause violent inflammation and death. 



Remedies: As these larvae are exceedingly tough, and 

 very difficult to kill even if immersed in fluids that would 

 kill all other insects, and as they are well hidden in the 

 stomachs of their hosts, all efforts to dislodge them are 

 more or less useless. Still some veterinarians claim good re- 

 sults with such substances as Bryonia root, 15 to 20 

 grammes powdered and given in half a pint of water; or tar,. 



