448 THE DISEASES AND DISORDERS OF THE OX. 



season. A small amount of spirits of tar may be added to the 

 oil and sulphur. 



We now pass on to the louse of the sheep, the creature 

 which is depicted in the figure which next meets the reader's 

 eye. 



The head of this creature is nearly orbicular, and the third 

 joint of the antennse is the longest and clavate. The scientific 

 name of the creature is Trichodectes spharocephalus. The 

 ticks, keds, or fags found on the skins of horses, cattle, 

 sheep, and dogs are parasitic species of the genus Ixodes, 

 and belong to the class of Aruchnida, of which spiders are also 

 members. 



The next creature we have to consider is the Melophagus 



Fig. 57. — The Tkichodectes sph^bocefhalus. 



ovinus, which attacks the sheep. It has no wings, and is dark 

 red in colour, except that the belly is white. It is often called 

 the sheep louse. According to Ray, it will live in a fleece for 

 twelve months after removal from a sheep's body. These ticks 

 are especially numerous on ewes in the spring, and when the 

 ewes are shorn, the lambs are tormented by the ticks passing 

 on to them from the ewes. Hence it is advisable to dip ewes 

 before shearing them, in order that these parasites may thereby 

 be killed. 



We now come to the consideration of verminous bronchitis 

 of lambs, a malady more generally known under the name of 

 husk or hoose, and one the outbreaks of which are sometimes 

 enormous in extent. Indeed, the disease is especially one of 



