THE RELATIONS OF ARACHNIDS TO MAN 127 



spraying the under surface of the leaves with a mixture of one 

 ounce of flowers of sulphur to one gallon of water. 



Gall Mites. — Certain mites that resemble the follicle mites 

 in appearance cause a common disease of the pear and apple 

 called pear-leaf blister, and are known as gall mites. 



REFERENCES 



Bulletins and Circulars published by the Bureau of Entomology and the 

 Bureau of Animal Industry, U. S. Department of Agriculture. 



