84 Mites Injurious to Domestic Animals. 



intercrural space, etc. Numerous specimens of Demodex in various 

 stages of development are to be found in the cheesy or fluid contents 

 of the nodules. The pustules or nodules may be situated in the 

 thickness of the skin instead of on the surface. A large number of 

 animals in a herd are sometimes found to be suffering from demo- 

 dectic mange ; hence it would seem to be infectious. According 

 to Van Saceghem, the general health does not usually seem to be 

 much affected. It is probable that the more serious cases of disease 

 in cattle attributed to Demodex by Geoffrey and one or two other 



FIG. 72. 



Raillietia auris (p. 91). A Gamasid mite living in the ear of cattle. 

 Dorsal view of female, X 47. (Original.) 



observers, are really due to infection with some bacterium. Stiles 

 states that the damage to the hides due to the enlarged holes caused 

 by Demodex bows lessens their value very considerably. The 

 disease seems fairly common in the United States. 



Demodex cam's, var. ovis, Eailliet, 1895. 



(F]g.50a.) 



The Demodex of the sheep is a slender, elongated form very 

 similar to D. cam's (and perhaps, indeed, the same species), but 



