PAKASITES 425 



A skin irritation in horses may be produced by the acari 

 of poultry, but the disease does not spread, and may be 

 cured spontaneously by removing the animals from the 

 affected area. 



Scabies or mange in animals, especially the horse and 

 sheep, is a most formidable disease from the rapidity with 

 which it spreads and the number affected. Being a highly 

 contagious malady, we may conveniently consider the 

 methods of stamping it out in the chapter dealing with 

 epizootic diseases. 



Insbota. — ^Under this head have to be considered the 

 various forms of Diptera (2-winged flies) which attack 

 animals, and the less formidable family of Pedicnlida, or 

 sucking lice. 



The Diptera may, as affecting animals, conveniently be 

 classified as follows : 



Culicidcs or Gnats. 

 Tabanidce or Gad-flies. 

 CEstridcs or Bot-flies. 



Muscida or House-flies, Stable-flies, and Sheep-mag- 

 got-flies. 

 Hippohoscidce, the Louse-flies, and Forest-fly. 



The Culieidce represent a vei-y important group of insect 

 pests to man, though their attack on animals is not com- 

 mon ; but a family to be mentioned presently, the SinmliidcB, 

 closely allied to the Culieidce, is a perfect plague to horses, 

 and may even cause death. Gnats and mosquitoes are 

 proved to be important as carriers of infection. It is quite 

 certain that the malarial fevers of man are conveyed by 

 a species of Anopheles (one of the mosquito group), and 

 another carries Yellow Fever. Filaria disease of man is 

 also transmitted in this way, likewise the Proteosoma of 

 birds, and there is good reason to believe that Horse-sick- 

 ness and Malarial Catarrhal Fever of Sheep of South Africa 

 are inoculated by another fly. 



In all the Culieidce it is the female which is the blood- 

 sucker, the males are harmless ; the sucking is accom- 



Digitized by Microsoft® 



