No. 4.] THREE SHADE-TREE INSECTS. 



239 



FiG.l. The Maple Borer. 

 (From Saunders.) 



layer of the tree. Soon, however, they burrow to the living 

 wood and commence their work of destruction. Many borers 

 feed only upon dead wood, but this insect apparently feeds 

 only upon living wood. The burrows or 

 grooves cut by the larvae generally run 

 upward, beneath the l)ark and partially 

 around the tree, although it is not rare to 

 find them running almost directly down- 

 ward. These grooves follow very irregu- 

 lar lines, are about one-half inch in width 

 by perhaps one-third inch in depth, and, 

 by passing around a part of the tree, cut 

 off the sap circulation in that part. Where 

 the larv« are abundant it is not an uncommon things to find 

 a tree entirely girdled by these grooves. 



It seems proliable that two years are required for the com- 

 pletion of the transformations of this insect. In examining 

 a number of infested trees I have found several burrows 

 entering the wood for an inch or two, half way in their 

 course, then coming out to the cambium again and continu- 

 ing to enlarge until the place for pupation is reached. From 

 this it might appear that the larva is only partly grown when 

 overtaken by winter and seeks shelter in 

 the trunk at this time, as well as when 

 preparing to pupate. In a recent letter 

 Dr. A. S. Packard expresses the opinion 

 that two years are required for the devel- 

 opment of this insec-t. 



When the larva approaches maturity it 

 usually enters the trunk for a short dis- 

 tance and forms a chamber, within which 

 it transforms to a pupa, from which, in 

 midsummer, the mature beetle emerges. 

 Under burlap bands placed on trees at 

 Maiden, Mass., to collect gypsy moth 

 attacked by the Jiapie larvfB, I havc fouud the uiaturc beetles as 

 ( )riginai.) early as June 24. The majority of the 



beetles, however, do not appear until July, during which 

 month they may be occasionally found on the blossoms of 

 goldenrods. 



Fig. 2. Trunk of a Maple 



