302 



METAZOAN PHYLA 



Other parasitic mites are the itch mites; the folHcle mites, which Hve 

 in the sweat glands and hair folUcles of man and some domestic animals: 



Fig. 



198.^A pseudoscorpion. {From Comstock, "The Spider Book"; copyright, 1912, by 

 the courtesy of Doubleday, Dora?i & Company, Inc.) X about 9. 



and the scab mites, which produce scabies. The animals generally known 

 in this country as chiggers are the larvae of red velvet mites. 



Mites that infest plants include the "red spider," which attacks house 

 plants; many that produce galls; and some that cause diseases of leaves, 



Cepfioilofhorax 



Fig. 199. — King crab, Limulus polyphemua (Linnaeus). 



xH. 



A, dorsal view. B, ventral. 



such as the one which causes the pear-leaf blister. Still other mites are 

 found in food products, such as cheese, sugar, and preserved meats. 



