io6 THE TREE BOOK 



her offspring are numerous enough to tunnel a 

 square foot of space, the tree will be kUled. As 

 a rule, however, bark beetles prefer dead or 

 dying trees, but it is certain that if they are 

 hatched in sufiBcient numbers they will attack 

 live trees. The forester's method of destroying 

 the bark beetle is to cut "trap trees." The 

 beetles attack these, and the "traps" are burned 

 before the young have time to appear. 



Here and there, in the winter time, we may 

 see what looks like a small band of shellac 

 painted on an apple twig. The microscope 

 shows that this band is really a circle of little 

 eggs, placed closely together, and covered with 

 water-proof varnish. It is the work of the 

 apple tree moth. Every banded twig destroyed 

 saves the tree from unsightly caterpillar tents, 

 or webs, the following season. For, with the 

 first warm days in spring, the varnish loosens 

 and tiny caterpillars emerge to feed upon the 

 opening leaves. How hungry they are ! If un- 

 disturbed, they wiU often entirely strip the 

 branch of foliage. Then they begin to spin a 

 silken web or tent for their comfort and shelter 

 at night and on stormy days. As they increase 

 in size, they range widely over the tree, and 

 often spin themselves down to the ground and 

 journey off to forage on other trees. In mid- 



