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The trees most commonly attacked are the maples, especially 
the silver-maple and the sugar-maple. It is difficult to find a 
maple which does not, or has not, harbored one or more of these 
borers. When entering the small branches the latter are weak- 
ened and often broken. If not broken, the bark originally cover- 
ing the excavation made by the insect soon decays, leaving large 
holes in the sides of the branches, retarding their growth and 
often killing them thus disfiguring the tree. When the insect 
has entered the main trunk the attempts on the part of the 
tree to heal the wound results in the formation of large unsightly 
scars. These wounds are also the gateways for the entrance of 
other insects and fungi, and the wood is gradually decayed, 
weakening the tree and destroying its beauty. As the trees 
become older the insects restrict their attacks to the branches 
rather than the main trunk. 
A large amount of damage has also been done to the ash-trees 
by thisinsect. It is difficult to find an ash-tree one to three inches 
in diameter in our grounds which has not been attacked by one 
or more of these borers and usually in their main trunks. One or 
two of these borers in the’ main trunk of a two-inch tree will 
so weaken and disfigure it that the tree is worthless. Probably 
more damage has been done to the young recently planted ash- 
trees in the Garden than to any other tree, doubtless due in part 
to the fact that more individuals of this tree are planted than of 
the other favorite hosts of this insect. 
The box-elder is also a favorite host for this insect and damages 
to this tree are similar to those of the maples. This is probably of 
minor importance, since the box-elder is not so commonly planted. 
A few sepcimens were also obtained from cultivated shrubs, 
Spiraea sp. and Viburnum opulus. 
The basswood is also subject to considerable injury. A number 
of large larvae have been removed from the main trunks of bass- 
wood trees planted in conspicuous places in our grounds, although 
on the whole this tree does not seem to be attacked to the same 
extent as the ash and maple. 
Several specimens were also obtained from the main trunks 
and smaller branches of the pin oak. 
