4 
been reported are in the District of Columbia and in the States 
of Virginia, West Virginia, Illinois, Wisconsin, and Michigan; but 
in all probability the same species has been more or less trouble- 
some in portions of Maryland, Pennsylvania, Indiana, and possibly 
Ohio, Kentucky, North Carolina, and Tennessee. With such a wide 
distribution there would be expected a considerable variation in the 
periods of appearance of the beetle according toclimate. In the lat- 
itude of the District of Columbia beetles have been captured no earlier 
than the last week of May, but they undoubtedly appear earher, and 
farther south issue from the wood probably at least as early as April. 
At Ithaca, N. Y., the writer has observed these beetles on oak from 
May 26 to June 16; at Rosslyn, Va., they were noticed as late as 
July 4. 
NATURE OF DAMAGE AND MANNER OF WORK. 
The two-lined chestnut borer works, in its larval stage, just under 
the bark of the tree, making galleries which run mainly transversely 
beneath the bark and which are, when completed, from 6 to 10 inches 
inlength. Although none have been observed that completely encir- 
cled a tree, the result, through the combined efforts of many 
individuals, is practically that of girdling. 
From the manner of the insect’s work it cannot be otherwise than 
injurious when it occurs in excessive numbers, as it undoubtedly 
stops the flow of sap, cuts off the natural supply of plant food and 
moisture, and thus greatly weakens and eventually kills the tree. 
The larval galleries occur from the base of the tree well up toward the 
top. Itis obvious that only the earlier stage of the larva is passed 
between the bark and the wood; indeed, it is likely that the entire 
life of the insect may be passed, in some instances at least, entirely 
within the bark. 
A knowledge of the full life history of the species was not obtained, 
but it is approximately as follows: In the District of Columbia the 
adult beetles make their appearance in May and the early part of 
June, the particular season for their appearance varying according 
to season and locality, and deposit their eggs upon the trees. The 
larvee work under the bark in the manner previously described, and 
by the following spring construct a chamber which, as far as observed 
in living trees, is always in the bark; but, in the case of small, dead 
trees, they work also in the wood under the bark, and in the cells 
thus formed transform into pup. The pupal stage lasts about two 
weeks or more, according to locality and season, when the beetles 
again issue from the trees and lay eggs for another brood. 
In addition to chestnut this species infests also white oak, scarlet 
oak (Quercus coccinea), and yellow oak (Q. velutina). 
