DemodecidcB, or Hair-follicle Mites 



79 



jointed legs, eight in number, are reduced to mere stubs in the adult. 

 The larval form is hexopod. These mites thus show in their form a 

 striking adaptation to their environment. In the sebaceous glands 



63. Demodex folliculorum. Section through skin showing the 

 mites in situ. Magnification of Nos. 1,2,6 and 7, X 150; 

 Nos. 3. 4, 5, X 450. After Megnin. 



and hair follicles they lie with their heads down (fig. 63). Usually 

 there are only a few in a gland, but Gruby has counted as many as 

 two hundred. 



The frequency with which they occur in man is surprising. Ac- 

 cording to European statistics they are found in 50 per cent to 60 per 

 cent or even more. Gruby found them in forty out of sixty persons 



