53 
Published accounts disagree as to the length of the life cycle of 
this species. It seems to be a single year under the most favorable 
conditions, but capable of being lengthened to two or even three 
years, particularly if the branch dies before the larva is full grown. 
As nearly all the borers pass the winter in the fallen twigs, it 
easily follows that their injuries may be readily arrested by gather- 
ing these up and burning them in winter or in spring. This efifec- 
tive measure is so simple and so easily applied that no other seems 
necessary. 
The Bronze Birch-borer 
(Agrilns anxius Gory) 
This insect is a deadly pest of the birches, especially of the beau- 
tiful and popular white birch, which it is quite capable of extermin- 
ating locally if its presence is not early detected and if prompt meas- 
ures are not then taken for its destruction. As an infested tree is not 
likely to last more than tw^o or three years, the necessity of energetic 
measures is obvious. Unfortunately, this insect does not usually 
make conspicuous local marks of the injury it is doing, and the 
earliest sign of its presence is often the death of one or more 
branches in the top of the tree. If a birch is seen to be dying at the 
top it should at once be examined for evidences of the presence of 
this borer, since in some cases this condition may be due to drought 
or other general causes. If the bronze borer be the cause, the fact 
may be ascertained by lifting the bark from dead branches which 
are not yet dry, or from the more unhealthy looking spots on the 
living parts of the tree. If the insect be present, its tortuous or 
zigzag burrows will be noticed, and further search will disclose the 
borer itself in one or more of its stages of larva, pupa, or adult. 
Sometimes, indeed, its presence is shown by a ridged appearance of 
the bark, the ridges running crosswise of the branches or in a more 
or less spiral direction. Peculiar rusty or reddish spots may also be 
seen on the larger branches or on the trunk where the bark has been 
undermined by the interlacing burrows of the borer. Often branches 
weakened by the borers and by consecjuent decay of the wood, break 
at the point of injury, either hanging down or falling from the 
tree. This appearance is rather characteristic of the work of the 
borers, and may serve to distinguish an infested tree from a "stag 
head," due to drouth. 
In its destructive stage this insect is a small, flattened, footless, 
creamy white grub about three-fourths of an inch long when full 
grown, with dark mouth-parts and a small head which is partly 
drawn back into the broad, flat, pale brownish, first segment of the 
body. At the opposite end is a pair of minute forceps-like spines, 
brown and hornlike, with two teeth on the inner edge of each. In 
this larval condition the borer mav be found in its burrows beneath 
