A. 



B. 



Fig. 269. — The "chigger" or harvest mite {Tromhicula sp.) of the class Arach- 

 noidea, highly magnified. The immature stage,. A, burrows in the skin and has 

 only three pairs of legs. The adult mite, B, has the typical four pairs of legs; 

 hence, it is not a true insect. (From Chittenden: Harvest Mites, or "Chiggers," 

 U. S. Department of Agriculture; courtesy of Bureau of Entomology and Plant 

 Quarantine.) 



Fig. 270. — The red spider (Tetranychus sp.) of the class Arachnoidea. This 

 adult female mite is greatly enlarged. (From McGregor: The Red Spider on Cot- 

 ton. U. S. Department of Agriculture; courtesy of Department of Entomology and 

 Plant Quarantine.) 



