1 8 Mites Injtirious to Domestic Animals. 



on sheep (Psoroptes communis, var. ovis, figs. 4 and 5) is of 

 great economic importance, being the cause of the serious 

 disease called sheep-scab, which damages the wool and also 

 occasions much loss of stock. Whilst the sarcoptic mange 



Fig. 4. 



Ventral view of male nymph of Psoroptes communis, var. ovis x 10 "> 



(a) Posterior end of female (pubescent) nymph, shovving the littfe 



pair of knobs that are grasped by the copulatory suckers of the 



adult male. (Original.) 



of the sheep is restricted to the head, the psoroptic occurs 

 on the parts of the body covered with wool. The mites 

 do not burrow in the skin, but pierce it with their elongated 

 mandibles. Irritation is intense, and the wool becomes detached 

 m places, also matted and full of gTeasy scabs or crusts Sheep 



