428 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



often making a complete band around a twig. They are 

 covered with a frothy, glue-like substance which protects them 

 during the winter and furnishes the first meals for the young 

 larvae. 



These pests have many natural enemies, such as birds, 

 Hymenopterous parasites and an important bacterial disease. 

 These help much to control them, but it is sometimes necessary 



FIG. 201. Egg mass and small tent of tent-caterpillar, 

 thirds natural size.) 



(About two- 



to resort to active methods of control. The eggs may be 

 pruned off in the winter and placed in a box covered with a 

 screen so that the parasites may be allowed to escape and the 

 larvae be retained when they hatch. The tents containing 

 the young larvae can be quickly gathered and destroyed when 

 they are small. Spraying very early, before the blossoms ap- 

 pear, with arsenate of lead will kill many of the larvae. 



Canker-worms. -The canker-worms, inch-worms, measur- 

 ing-worms, or loopers are common throughout nearly all parts 



