HEMIPTERA 



65 



parently, for the greater part of their lives, inanimate 

 objects on the bark of trees. They are usually less than 

 one-eighth of an inch in diam- 

 eter, oval or circular in outline, 

 and more or less flattened. The 

 young and the adult males have 

 eyes and appendages and move 

 about. Other stages fasten them- 

 selves to the host-plant by means 

 of their beaks and also by a 

 waxy secretion. They are pro- 

 tected either by a separate scale 

 which is formed over them from 

 secretions of their bodies, but 

 not attached to them, or by a 

 hardening of the body wall it- 

 self. Scales in the latter group 

 are known as unarmored scales 

 while the others are called ar- 

 mored scales. Scale insects feed for the most part on 

 shrubs and woody plants, but some are found on grasses 



FIG. 40. San Jose Scale on 

 'Apple Bark 



FIG. 41. The Tulip Scale. 



and on ferns and other greenhouse plants. Mealy bugs, 

 which are also Coccids, feed on herbaceous plants. Some 



