236 PARASITIC DISEASES 



from the nostrils. The irritation produced by the larvse may be 

 so serious at times as to result in nervous symptoms and death. 



Treatment of Bot-fly Diseases. — The treatment of the differ- 

 ent bot-fly diseases is largely preventive. This consists in either 

 the destruction of the eggs or the larvae 



The different methods of destroying the eggs of the bot-fly 

 of the horse are clipping the hair from the part, scraping off 

 the eggs with a sharp knife, or destroying them by washing the 

 part infested with eggs with a two or three per cent water solu- 

 tion of carbolic acid. This should be practised every two weeks 

 during the period when the female deposits the eggs. 



Housing the cattle, or applying water solutions of certain 

 preparations to the skin that may keep the female from deposit- 

 ing eggs, may be practised for the prevention of the ox-warble. 

 The most practical method of ridding cattle of this pest is to 

 destroy the larvic. This can be done by examining each animal 

 and locating the swelling or warble and injecting a few drops 

 of kerosene into the opening in the skin. A better method is to 

 enlarge the opening in the skin with a sharp knife, squeeze out 

 the grub and destroy it. This should be practised in late winter 

 and early spring. 



The application of pine tar to the nostrils of sheep is the 

 most practical method of preventing " grub in the head." This 

 should be practised every few days during the summer months. 

 A very good preventive measure is plenty of shade for the flock. 

 Valuable animals may be treated by trephining into the head 

 sinus and removing the " grub." 



Lice. — The sucking lice belong to the genus Ilcematopinus, 

 and the biting lice of mammals belong to the genus Trichodectes. 

 Different species of sucking and biting lice occur on the different 

 species of farm animals. Poultry act as hosts for many differ 

 ent species of biting lice belonging to the following genuses: 

 Lipiurus, Goniodes, Goniocotes and Menopon. 



The common sucking lice occurring on animals are the large- 



