124 



BULLETIN 67, UNITED STATES NATIONAL MUSEUM. 



Many are parasitic on man or other animals. The red spiders 

 (Tetranychidse) (fig. 183) are soft-bodied forms, feeding on the foliage 

 of trees and plants, and they spin a thread wherever they go. The 

 harvest mites (Trombidiidse) are large, red 

 mites sometimes seen wandering in the spring- 

 time. Their larvae are called "red bugs," and 

 attack people as well as animals. The cheese 

 mites (Tyroglyphida?) (fig. 184) feed on stored 

 foods, cheese, flour, seeds, dried fruits, and the 

 roots of plants. They are soft-bodied, and 

 of a pale whitish color. The ticks (Ixodoi- 

 dea) are larger than most mites, and with a 

 tough, leathery skin. They have a breath- 

 ing pore in a granulated plate just above 

 the hind legs. The cattle tick (Margaropus 

 annulatus) (fig. 185) is the carrier of Texas 

 fever, and the Rocky Mountain tick (Dermacentor venustus) is the 

 disseminator of spotted fever. The scab or itch mites (Sarcop- 



flg. 182.— a false scorpion, 

 Chellfer cancroides. 

 (From Packard.) 



Fig. 1S3.— The Six-spotted mite of the 

 orange, Tetranyciius 6-maculatus: 

 o, From above; 6, tarsus; c, rostrum 

 and palpus; d, tip of palpus, a, 

 Greatly enlarged; 6, c, more en- 

 larged; d, still more enlarged. 



Fig. 184. — A cheese mite, Tyroglyphus. 



tidse) are small, soft-bodied forms that burrow in the skin of 

 various animals, including man, thereby causing scabies, a disgust- 

 ing disease. The Eriophyidse, or gall-mites (fig. 186), are so small 



