THE CANADIAN ENTOMOLOGIST. 



irritation produced by so many larvae at work, cause an increased flow of 

 sap to the part, and a consequent thickening of the sections between the 

 slits, so that the injured part soon assumes a gall-like appearance. On 

 the approach of winter, the larvse having now attained the length of .25 

 inch, retire back a little further and close the opening of their burrows 

 with borings. One of the larvse, however, and in thick limbs two or three 

 at each end bore obliquely till one of them reaches the centre of the limb, 

 up which it proceeds, often two or three inches ; the ethers parallel this, 

 but keep a wooden partition between the burrows. These larvae are 

 much larger — often twice the size — of those inhabiting the outer wood, 

 and are the only ones that produce beetles. 



The whole of the interior of the limb is now dead wood enclosed by 

 a growth of living but unsound woody tissue, through which some open- 

 ings remain. The limbs are much weakened at these places, and many 

 of them, like the oak on which Elaphidion villosum depredates, would 

 be broken off by the winter storms were the fibre not very tough and the 

 trees very low. And here analogy leads to the conclusion that as the 

 larvae inhabit the portion of the limb next the tree, equally with that 

 beyond the injured part, this is likely to be the case in the history of the 

 Elaphidion mentioned. 



Many of the larvae in the outside wood perish during tjie winter, and 

 the survivors, after feeding a while in the spring, likewise die, their mis- 

 sion seeming to have been merely to insure a sufficiency of dead wood to 

 sustain the life of the favored few destined for full development. 



In the spring the larvae in the deep wood return and feed on the dead 

 wood, which is now abundant enough for all their wants, and by autumn 

 they are nearly full grown ; they again retire for the winter, and in the 

 spring, after opening up communication with the outside world, feed for a 

 short time, and when full grown measure in length about three fourths of 

 an inch. The larvae now return to their burrows for final transformation. 

 Some of them bore for at least six inches, while others scarcely go from 

 the entrance more than twice their own lengths ; the outer ends are 

 closely packed with borings withont and soft fibre within, which also fills 

 the inner ends. The head of the larva may be either toward or away 

 from the opening — seemingly a matter of indifference ; in the former case 

 the beetle emerges from the place of entrance, in the latter from a round 

 hole at right angles to the burrow, probably cut by the beetle itself, as no 

 such hole has been detected in the many limbs I have examined contain- 



