244 
HALF HOUHS WITH mSECTS. [Packard. 
above the place where it is partially severed, until a high 
wind occurs. If the limb is not hereby broken, as soon as 
the weather becomes calm he very probably returns and 
gnaws off an additional portion of the wood, repeating this 
act again and again, it may be, until a wdnd comes which 
accomplishes the desired result. And this serves to explain 
to us why it is that the worm severs the limb at such an 
early period of his life. For the formidable undertaking of 
cutting asunder such an extent of hard woody substance, we 
should expect he would await till he was almost grown and 
had attained his full strength and vigor. But by entering 
upon this task when he is but half grown he has ample 
opportunity to watch the result, and to return and perfect 
the work if he discovers that his first essay fails to accom¬ 
plish the end he has in view. 
“Thus the first part of the life of this worm is passed in a 
small twig branching off from the main limb. This is so 
slender and delicate that on being mined as it is by the 
worm and all its green outer end consumed, it dies and be¬ 
comes so decayed and brittle that it is usually broken off 
when the limb falls, whereby it has escaped the notice of 
writers, hitherto. The remainder of his larval life is passed 
in the main limb, first cutting off this limb sufficiently for it 
to break with the force of the winds, and then excavating a 
burrow upwards in the centre of the limb, both before and 
after it has fallen to the ground, feeding hereon until he has 
grown to his full size.” 
Fitch adds that “not only the limbs, but small young 
trees, at least of the white oak, are sometimes felled by 
these insects ; in which cases the worm instead of cutting 
the w'ood off transversely, severs it in a slanting or oblique 
direction, as though it were aware the winds would prostrate 
a perpendicular shoot more readily by its being cut in this 
manner.” 
The larvae become fully grown in the autumn, and some 
20 
