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In various places this moth has been reported as doing great 
damage to the elm. Although there is some evidence outside 
of the Garden that the elms are attacked, so far not a single 
elm has been found to contain this borer within our grounds. 
Of course it has been impossible to examine the branches of the 
larger trees, and although it has not yet been found on our elms 
it is probable that the elm is also subject to the attacks of this 
insect. 
It has been reported as attacking the tulip-tree, but none of 
our trees have thus far been found to be infected. The sycamore 
also seems thus far to be free from it. 
MertHops oF DETECTING ITS PRESENCE. 
During the early process of the boring the partly digested 
wood is thrown out of the opening made as the larva enters the 
tree and falls to the ground below. After the cavity becomes 
sufficiently large the opening is carefully closed by a whitish 
semitransparent web-like membrane. The opening through 
which the larva entered the tree being at this time completely 
covered, it is difficult to detect the point of attack except as 
guided by the droppings below. The wood around the wound 
however is usually darkened by the flow of sap, so that this 
will aid in locating the exact spot. The droppings are so char- 
acteristic that one can be reasonably certain of the presence 
of these insects by examining the ground underneath the tree. 
Guided by this the exact point of attack can also be located. 
On one occasion the position of a large borer was located in 
the trunk of a young ash-tree and a small hole was cut to 
make sure of the presence of the insect. Having no means 
of removing the larva it was left until the following morning. 
At this time the same tree was visited and it was found that 
the larva had carefully recovered the hole made into its burrow. 
It was again opened and the larva—in this case about two inches 
in length—was removed. 
The first step then in determining the presence of these insects 
is to carefully examine the ground under the tree for their char- 
acteristic droppings. It is then only the matter of a little time 
to locate the point at which the insect has entered the tree. 
