82 Mites Injrtrious to Domestic Animals. 



withers and croup, the lower parts of the belly being rarely afiected 

 at this stage. The lower third of the neck is the usual site of 

 origin. Little can be seen, but epidermal scales will be noticed to be 

 more numerous than is usual on a well-groomed horse. 



In the second or more advanced stage the presence of j)ustules is 

 the most striking symptom. Cutaneous irritation is very much less 

 marked, but a certain thickening of the skin will always be noticed. 



Fig. 70. 

 Protonymph of Liponyssus bursa (p. 



), dorsal aspect, X 101. 



' Demodex phylloides, Csokor, 1879. 



(Fig. 50, c and d.) 



The Demodex of the pig is rather wide, the female being only 

 about three and a half times as long as the width of the cephalo- 

 thorax ; the posterior end of the body is abruptly narrowed so as to 

 form a short tail. Tubercle on capitulum very short and incon- 

 spicuous 



D. fhylloides causes a pustular skin disease in pigs, the pustules 

 varying from a grain of sand to a walnut in size. They are often 

 very numerous, and may be situated close |together ; sometimes 

 they become confluent, and may rupture and cause sores and ulcers 

 on the skin. Large numbers of the parasites are present in these 



