PARASITIC DISEASES. 165 



5. Lice. 



Trichocephalus spherocephalus ; common sheep 

 louse. 



This is a very small white and reddish brown 

 parasite, measuring about one-twentieth of an 

 inch in length. The eggs are laid at the base 

 of the wool fibers. 



Only a very careful examination reveals the 

 true cause of the irritation, as the symptoms are 

 much like scab. In the heat of the day, the lice 

 will be found to be sticking to the outer end of 

 the wool fiber. 



If many animals are infected dipping with any 

 coal tar dip is advisable. If only a few, an oint- 

 ment composed of equal parts lard and sulphur, 

 rubbed into the affected parts, will soon eradicate 

 the lice. 



6. Maggots. 



Embryo of the Musca vomitorium or common 

 blow-fly. 



This is one of the most serious pests with 

 which the sheep man has to contend. When a 

 sheep is accidentally cut during shearing, or re- 

 ceives some other injury breaking the skin, the 

 blow-fly attacks the -helpless animal. Sometimes 

 the wool becomes overlaid with fetid discharges 

 such as urine, feces, or pus, and here the fly lays 

 her eggs. Soon a festering mass of maggots 

 are present, and which in a large band are often 

 not discovered until the animal is nearly dead. 



The treatment consists in getting the maggots 

 out of the sore, and painting the edges with tine- 



