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 larvee, 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 
eould 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 larve 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. 
Vv 
