Circular No. 1 58. 



Issued .Tulv 27, 1911 



United States Department of Agriculture, 



BUREAU OF ENTOMOLOGY. 

 L. O. HOWARD, Entomologist and Chief of Bureau. 



THE CLOTER MITE. 



(Bryohia pratcnsis Garman.) 



By F. M. Webster, 



In Charge of Cereal and Forage Inseet Investigations. 



INTRODUCTION. 



The minute organism known as the clover mite (fig. 1) is not a 

 true insect, but belongs, with the spiders, to a very extensive group 

 the adults of which possess 

 eight legs, whereas true in- 

 sects have only six legs. 



There are a great many 

 species of these mites and 

 they differ widely among 

 themselves in habits. Some 

 make galls on the leaves of 

 trees and shrubs ; some, like 

 the one which commonly at- 

 tacks the currant, are known 

 as blister mites, as they 

 cause blisters on leaves; 

 others are parasitic on man, 

 as the itch mite; while still 

 others, like the Trombidium, 

 are parasitic on insects. 

 Another, Pedlciiloides ven- 

 iricosiis Xewp., is parasitic 

 on insects but also attacks 

 man. The one here treated 

 lives on the surface of 

 leaves of trees and plants, 

 but does not cause galls or 

 blisters. It is a near relative 

 of the notorious red spider. 



The clover mite, also known as the brown mite, is of a twofold 

 interest. It attacks the leaves of clover, grasses, and fruit and other 



1 



Fig. 1. — The clover mite (Btyohin pratensis). 

 Enlarged ; natural size shown by line at right. 



(From Insect Life.) 



