84 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



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. 

 Late in August, 1888, this borer was reported to be especially abundant 

 in Warwick, R. I., so that the ground was said to be strewn with the 

 smaller branches of oak and locust trees. We are indebted to Dr. Fitch 

 for the most detailed information regarding this curious longicoru : 



The severed limbs are usually but eigliteen iucbes or two feet iu length, but Pro- 

 fessor Peck states that limbs an inch in thickness and five feet in length are sometimes 

 found. I have seeu a limb cut off by this insect which was ten feet in length and an 

 inch and a tenth iu 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 oflf 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, iu the angle where one of the leaf-stalks branches off from it. The 

 young worm which hatches therefrom sinks himself into the center of the twig ctud 

 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 sufiScieut size and strength to attack the more solid woody portion 

 forming its lower end. He accordingly eats his way downward iu 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 an inch 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 iu 

 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 which 

 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 cirtting 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 

 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. If it be very long and heavy 



