36 



CLASS ARACHNIDA 



pay a rather exorl)itant price for a few simple chemicals, 

 and further, in case of the arsenical dips, that he may not 

 know the ingredients or their proportions and thereby endan- 

 ger tlie animals treated. 



The Itch Mite. — The itch mite, or "itch insect," afl'ecting 

 man is perhaps becoming a rather rare pest in civilized 

 communities, but since it occurs at times on domestic 

 animals, and in certain varieties becomes at times a serious 

 pest to such animals, it deserves mention here. Authors 



Fig. 16. — Sarcoptes scabiei: male and female. (Reduced from 

 Furstenberg, after Murray.) 



have differed greatly in their treatment of the species, some 

 making a different species for each host animal, believing 

 that they could find distinctive characters in the size, 

 arrangement of spines, etc.; but recent authors have com- 

 bined most of these under the one species, scabiei, though in 

 some cases retaining the varietal distinction for various 

 hosts. 

 All stages of the parasite occur on the host upon which 



