Bots in Sheep 337 



especially if the ground is dusty; they also collect in 

 bunches with their heads together for protection. The 

 larva, as soon as it is deposited in the nostril, makes its 

 way up the nose into the sinuses or cavities connected 

 with the nasal chambers, where it attaches itself to the 

 mucous membrane by two small hooks. Here it remains 

 until fully developed, when it loosens its hold and drops 

 to the ground to pupate. Finally, an adult fly emerges. 



While the larvae, or grubs, are in the sinuses of the 

 head, they cause great irritation. The animal snorts and 

 blows the nose, and there is discharge of pus and 

 mucus from the nostrils. The harm done by this pest 

 is due to the annoyance and worry that it causes the 

 sheep. The writer has never seen a case where death 

 could be directly attributed to this fly. There is a dis- 

 ease due to another parasite, called "gid" or "sturdy," 

 which is often confused with the sheep bot, that does 

 cause death; but this pest seldom occurs in America. 

 See page 340. 



The best treatment consists in preventing the fly 

 from depositing the larvae in the nostrils of the sheep; 

 this may be accomplished by keeping the sheep's nose 

 well smeared with pine -tar. When there are but few 

 sheep, the tar can be applied by catching the animals; 

 when there are large numbers, salt is usually put in the 

 bottom of V-shaped troughs, the sides of which are 

 thoroughly smeared with tar. It is a good plan to 

 apply tar once a week during the fly season. When 

 sheep are seriously affected, they may be sent to the 

 shambles. If valuable, a good surgeon should be em- 

 ployed to remove the parasites. 



