31 



FiG.l. The Maple Borer. 

 (From Saunders.) 



deposits the eggs. The eggs batch in a short time and give rise 

 to small white grubs, which " mine" the bark for a short distance 

 before attacking the cambium 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 appar- 

 ently feeds only upon living wood. The 

 burrows or grooves cut by the larvffi gen- 

 erally run upward, beneath the bark and par- 

 tially around the tree, although it is not rare 

 to find them running almost directly down- 

 ward. These grooves follow very irregular 

 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 larvoe are abundant it is not an uncommon 

 thing to find a tree entirely girdled by these grooves. 



It seems probable that two years are required for the completion 

 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 continuing to enlarge until the place for pupa- 

 tion 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 develop- 

 ment of this insect. 



When the larva approaches maturity it 

 usually enters the trunk for a short distance 

 and forms a chamber, within which it trans- 

 forms to a pupa, from which, in midsummer, 

 the mature beetle emerges. Under burlap 

 bands placed on trees at Maiden, Mass., to 

 collect gypsy moth larvffi, I have found the 

 mature beetles as early as June 24. The 

 attacked by the Maple majority of the bcctlcs, howcvcr, do not 

 Borer. (Original.) appear Until July, during which month they 



may be occasionally found on the blossoms of goldenrods. 



Dr. Harris describes the mature beetle as follows : " The 

 beetle is black, with a yellow head, with the antenna and the 

 eyes reddish-black ; the thorax is black, with two transverse yel- 

 low spots on each side ; the wing-covers for about two-thirds of 





Fig. 2. Trunk of a Maple 



