THE BORERS OF CERTAIN SHADE TREES. 589 
“great numbers of the larve of C. tridentata in the bark 
and between the bark and the wood, while the latter is 'tat- 
tooed’ with sinuous grooves in every direction and the tree 
is completely girdled by them in some places. . There are 
three different sizes of the larve, evidently one, two and 
three years old, or more properly six, eighteen and thirty 
months old." The tree had to be cut down. 
Dr. Harris, in his Treatise on injurious insects, gives an 
account of the ravages of this insect which we quote: "On 
the 19th of June, 1846, Theophilus Parsons, Esq., sent me 
some fragments of bark and insects which were taken by 
Mr. J. Richardson from the decaying elms on Boston Com- 
mon, and among the insects I recognized a pair of these 
beetles in a living state. The trees were found to have suf- 
fered terribly from the ravages of these insects. Several of 
them had already been cut down, as past recovery ; others 
were in a dying state, and nearly all of them were more or 
less affected with disease or premature decay. Their bark 
was perforated, to the height of thirty feet from the ground, 
with numerous holes, through which insects had escaped ; 
and large pieces had become so loose, by the undermining 
of the grubs, as to yield to slight efforts, and come off in 
flakes. The inner bark was filled with burrows of the 
grubs, great numbers of which, in various stages of growth, 
together with some in the pupa state, were found therein; 
and even the surface of the wood, in many cases, was fur- 
towed with their irregular tracks. Very rarely did they 
seem to have penetrated far into the wood itself; but their 
operations were mostly confined to the inner layers of the 
bark, which thereby became loosened from the wood be- 
neath. The grubs rarely exceed three-quarters of an inch 
a length. They have no feet, and they resemble the larve 
of other species of Saperda, except in being rather more 
flattened. They appear to complete their transformations in 
the third year of their existence. 
“The beetles probably leave their holes in the bark during 
