32 ‘INSECTS INJURIOUS TO FOREST AND SHADE TREES. 
makes a mistake of this kind. If the limb be short it severs all the woody fibers» 
leaving it hanging only by the outer bark. If it be longer a few of the woody fibers 
on its upper side are left uncut in addition to the bark. Ifit be very long and heavy 
not more than three-fourths of the wood will be severed. The annexed figures repre- 
sent the several ends of limbs of different sizes, the coarsely dotted parts of the two 
first indicating the ragged broken ends of the woody fibers, the remainder being the 
smooth surface cut by the worms, and the large black dot representing the perfora- 
tion leading up the limb to where the worm lies. The first of these figures was taken 
from the limb already spoken of as ten feet in length, and here it will be noticed that 
a portion of the stouter wood towards the center of the limb was preserved, as though 
the worm had been aware that the weaker sappy fibers outside next to the bark could 
not be relied upon for sustaining a limb of this size, as they are where the limb is 
smaller. With such consummate skill and seemingly superterrestrial intelligence does 
this philosophical little carpenter vary his proceedings to meet the circumstances of 
his situation in each particular case! But by tracing the next stage of his life we 
shall be able to see how it is that he probably performs these feats which appear so 
much beyond his sphere. 
Having cut the limb asunder so far that he supposes it will break with the next 
wind which arises, the worm withdraws himself into his burrow, and that he may 
not be stunned and drop therefrom should the limb strike the earth with violence 
when it falls, he closes the opening behind him by inserting therein a wad formed of 
elastic fibers of wood. He now feeds at his leisure upon the pith of the main limb, 
hereby extending his burrow up this limb six or twelve inches or more, until he at- 
tains his full growth—quietly awaiting the fall of the limb, and his descent therein 
to the ground. It is quite probable that he does not always sever the limb sufficiently, 
in the first instance, for it to break and fall. Having cut it so much as he deems 
prudent, he withdraws and commences feeding upon the pith of the limb 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 wind comes which accomplishes the desired result. And this serves 
to explain to us why it is that the worm severs the limbs 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 his first essay fails to accomplish 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 becomes 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 larva 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 center of the limb, both before and 
after it has fallen to the ground, feeding hereon until he has grown to his full size. 
It is most frequently the limbs of the red and the black oak that I have met with, 
severed by the oak pruner, though it is not rare to find those of the scarlet oak (Q. 
coccinea) and of the white oak lopped off in the same manner. Limbs of the beech 
and chestnut not unfrequently, and those of the birch, the apple, and probably of 
other trees, are sometimes similarly severed. Mr. P. Weter, of Tirade, Walworth 
County, Wisconsin, informs me that the peach in his vicinity suffers in a similar 
manner, and to such an extent some years, that the severed limbs, varying from a few 
inches to two feet in length, are seen lying under almost every tree. We have in our 
country several species of beetles very closely related to the oak pruner, but no at- 
tempts have yet been made to ascertain their mode of life. It is very probable that 
