THREE COMMON SCALE INSECTS. 



BY H. T. FERNALD, PH.D. 



Fruit growers often find scale insects (formerly called bark 

 lice) on their trees, and of these there are three kinds which 

 are abundant in Massachusetts. These are known as the 

 San Jose scale, the 

 oyster-shell scale 

 and the scurfy 

 scale. 



The Sax Jose 

 Scale. 



This pest, which 

 is the most destruc- 

 tive scale we have, 

 is now generally 

 distributed in the 

 State. 



The scale is 

 round (circular) in 

 outline, or nearly 

 so, and when full 

 grown is about as 

 large as a small pin 

 head, highest in the 

 middle and grayish- 

 brown in color. 



The young are born alive, beginning about the middle of 

 Jime, and are produced at intervals of two or three days for 



Fig. 1. — Different stages of the San Jos4 scale, enlarged 

 five times. (From Virginia State Crop Pest Commis- 

 sion Bulletin, 1904.) 



