THE DAVEY INSTITUTE OF TREE SURGERY 
the form of a spiral attached to the bark, 
and an inch or more in length. 
61. Later, when the tree attempts to 
heal the burrow, the bark is pushed up in 
the form of a ridge following the burrow. 
The burrows usually run upward and 
around the trunk or limb, but may run in 
other directions in certain cases. Frequently 
they cut off an area of bark, causing it to 
die and peel off, especially if two or more 
borers are working in the same tree. 
62. Habits. The large black, cylindri- 
cal beetles, with yellow head and legs and 
conspicuous yellow markings on the back, 
appear in July and August, and begin lay- 
ing eggs in obscure gashes in the bark. On 
hatching, the larve burrow into the bark or 
just into the cambium, and there pass the 
first winter. 
63. The following summer they pen- 
etrate the cambium and feed until the ap- 
proach of the second winter, when they 
penetrate deeper into the wood. ‘The 
second spring the burrowing is continued 
under the bark, but at a more rapid rate. 
A short time before pupating they again 
enter the hard wood, working inward and 
upward, forming a chamber in which to 
pupate. The total length of the burrow 
may vary from one to three feet. The bur- 
row at the last is one-half inch wide and 
one-third inch deep. 
64. Control. From what has been said, 
you can see the dangerous nature of the 
Courtesy New York State 
Entomologist. 
Fig 4. 
Sugar maple borers, 
natural size. The lower 
one a male and the others 
females. Note the vari- 
ations in the markings. 
After J. A. Lintner. 
work of this insect, and the difficulty of reaching it after it once 
penetrates well into the tree. To attempt to follow the burrow 
and kill a nearly full-grown larva would make a serious wound 
inthe tree. 
65. This can be avoided by the use of repellents during July 
and August to prevent egg laying, or by locating and killing the 
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