ITCH MITE. 



125 



We should also mention the Mange Insect of the horse 

 (Psoroptes equi, Fig. 149, much enlarged; a, head more magni- 

 fipd). According to Prof. Verrill it is readily visible to the 

 naked eye and swarms on horses afflicted with the mange, which 



149. Mange Blite. 



150. Itch Mite. 



is a disease analogous to the itch in man. It has a soft, 

 depressed body, spiny beneath at the base of the legs and on 

 the thorax. One or both of the two posterior pairs of feet bear 

 suckers, and all are more or less covered with long, 

 slender hairs. This insect may be destroyed by the ^/IKi 

 same remedies as are used for lice and'for the human w\>^ 

 itch. The best remedy is probably a solution of sul- ^;g^g9e. 

 phuret of potassium. 



The itch insect (Sarcoptes scabiei. Fig. 150) was first 

 recognized by an Arabian author of the twelfth cen- 

 tury, as the cause of the disease which results from 

 its attacks. 'The body of the insect is rounded, with 

 the two hind pair of feet rudimentary and bearing 

 long hairs. It buries itself in the skin on the more 

 protected parts of the body, and by its punctures isi.Nose 

 maintains a constant irritation. Other species are Mite. 

 known to infest the sheep and dog. Another singular mite is 

 the Demodex foUiculorum (Fig. 151), which was discovered by 

 Dr. Simon, of Berlin, buried in the diseased follicles of the wings 

 of the nose in man. It is a long, slender, worm-like form, with 



