. INSECTS INJURIOUS TO THE OAK. aL 
limb, whether conscious or not of any design in the matter, is probably, as 
Peck first suggested, to afford the grub a sufficiently moist retreat to 
live in during the winter. He supposed that the limb thus wounded 
would become too dry for the maintenance of the soft-bodied larva, . 
hence it must be felled to the ground, where in the wet and under the 
snows of winter it would remain sufficiently moist for the existence of 
the insect, which completes its transformation within. 
Mr. C. A. Walker has brought us the insect in its different stages cut 
out of oak branches, which occurred in abundance at Chelsea, Mass., 
but, as seen by the following extracts, we are indebted to Dr. Fitch for 
the most detailed information regarding this curious longicorn. 
The severed limbs are usually but eighteen inches or two feet in length, but Profes- 
sor Peck states that limbs an inch in thickness and five feet in length are sometimes 
found. I have seen a limb cut off by this insect which was ten feet in length and an 
inch and a tenth in thickness, and have repeatedly met with them seven and eight 
feet long and usually an inch, but in one instance an inch and a quarter, in thickness. 
The parent beetle seems aware that her progeny in their infancy will be too feeble 
to masticate the hard woody fibers of the limb. She, therefore, selects one of the 
small twigs which branch off from it, which is not thicker than a goose quill, with its 
base composed of soft wood, the growth of the last year, all the remainder of the twig 
being the green succulent growth of the present year. She places her egg near the 
tip of this twig, in the angle where one of the leaf-stalks branch off from it. The 
young worm which hatches therefrom sinks himself into the center of the twig and 
feeds upon the soft pulpy tissue around him until it is all consumed, leaving only the 
green outer bark, which is so thin and tender that it withers and dries up, and ere 
long becomes broken. By the time this green tender end of the twig is consumed the 
worm has acquired sufficient size and strength to attack the more solid woody portion 
forming its lower end. He accordingly eats his way downward in the center of the 
twig, consuming the pith, to its base, and onward into the main limb from which this 
twig grows, extending his burrow obliquely downward to the center of the limb, to a 
distance of half an inch or aninch below the point where the lateral twig is given off. 
The worm being about half grown, is now ready to cut the limb asunder. But this 
is a most nice and critical operation, requiring much skill and calculation; for the 
’ limb must not break and fall while he is in the act of gnawing it apart, or he will be 
crushed by being at the point where it bends and tears asunder, or will fall from the 
cavity there when it breaks open and separates. To avoid such casualties, therefore, 
he must after severing it have time to withdraw himself back into his hole in the 
limb and plug the opening behind him before the limb breaks and falls. And this 
little creature accordingly appears to be so much of a philosopher as to understand 
the force of the winds and their action upon the limbs of the tree, so that he can bring 
them into his service. He accordingly severs the limb so far that it will remain in its 
position until a strong gust of wind strikes it, whereupon it will break off and fall. 
But the most astonishing part of this feat remains to be noticed. The limb whieh 
he cuts off is sometimes only a foot in length and is consequently quite light; some- 
times ten feet long, loaded with leaves, and very heavy. A man by carefully inspect- 
ing the length of the limb, the size of its branches, and the amount of foliage growing 
upon them could judge how far it should be severed to insure its being afterwards 
broken by the winds. But this worm is imprisoned in a dark cell only an inch or two 
long in the interior of the limb. How is it possible for this creature, therefore, to 
know the length and weight of the limb and how far it should be cut asunder? A man, 
moreover, on cutting a number of limbs of different lengths, so far that they will be 
broken by the winds, will find that he has often miscalculated, and that several of the 
limbs do not break off as he designed they should. This little worm, however, never 
