THE ACARUS WHICH CAUSES SCAB. 



The figure at the left represents the female of 360 times the natural 

 size, provided with eight legs ; four before, and four behind. 



a, — The sucker. 



6, b, b, b, — The four anterior feet, with their trumpet-like appendages. 



C,c, — The two interior hind feet. 



d,d, — The two outward feet, the extremeties of which are provided with 

 long hairs, and on the other parts of the legs are shorter hairs. To 

 these hairs the young acari adhere when they first appear from the 

 pustule. 



e, — The tail, containing the anus and vulva. 



The figure at the right, is the male on its back, seen by the same 

 magnifying power. 

 a, — The sucker, 

 ft, 6, 6, &,— The fore legs. 

 C, C, — The outer hind legs. 

 d, d, — The rudimentary abdominal legs, 

 e,— The tail. 



