THE BIRCH LEAF SKELETONIZER 263 



burrows are always packed with castings of the grub. It lives in 

 the larval stage until the latter part of the following spring, trans- 

 forming to a pupa within the burrow. A month later it changes 

 to the adult form, and escapes from the tree in late June. 



Injury. It then feeds on the leaves of trees. This insect 

 infests all varieties of birch, and it is sometimes claimed that it 

 attacks willows. Trees of large size are often killed by these 

 borers within three or four years, and it is a common sight .to 

 observe large birch trees dying from the top as the result of attacks 

 from this insect. 



Control. When this condition is observed, the only remedy 

 practicable is to cut infested trees below the injured portion, 



FIQ. 263. Imperfect galls on leaves of maple. Fia. 264. Fly raised from galls 



on maple. 



taking pains to cut low enough to remove any portions infested 

 by the grubs. These cut-off portions should be burned. This 

 pruning should be done in winter or early spring. 



The Birch Leaf Skeletonizer. This is a brown moth (Buccu- 

 latrix canadensiella Cham.) less than one-half inch in length. 

 The wings are crossed with delicate white bars. The green cater- 

 pillar or larva has a brownish head; it is quite slender and tapers 

 slightly toward the anterior and posterior ends. When disturbed, 

 it may lower itself by means of a silken thread from the leaves. 

 The cocoon is brownish or yellowish hi color and one-fourth' of 

 an inch long. It is attached to the leaf or twig. 



This is a serious pest of the birch. It feeds on the soft parts of 

 the leaf, leaving only the brownish skeleton. In late summer this 

 injury is conspicuous. 



