ATTACKING THE TRUNK. ] 93 



different sizes all through the fall and winter months, some 

 quite young associated with others nearly full grown. During 

 the winter the larger ones rest, with their heads upwards, in 

 smooth, longitudinal grooves which they have excavated, the 

 back part being covered with castings mingled with gum and 

 silken threads, forming a kind of cell, the cavity of which is 

 considerably larger than the worm inhabiting it; the smaller 

 ones usually lie in the gum, or between it and the wood of the 

 trunk or root. In badly-infested trees the whole of the bark 

 at the base or collar is sometimes consumed for an inch or two 

 below the surface. Nor does the insect always confine itself 

 to the base of the tree ; occasionally it attacks the trunk farther 

 up, and sometimes the forks of the limbs ; but the exuding 

 gum invariably points out the spot where the foe is at work. 



When about to become a pupa, the larva crawls upwards 

 to the surface of tho ground, and constructs a pod-like case, 

 of a leathery structure, made from its castings mixed with 

 gum and threads of silk. It is about three-quarters of an 

 inch long, of a brown color, oval in form, with its ends 

 rounded ; its inner surface is smooth, and it is fastened against 

 tlie side of the root, often sunk in a groove gnawed for that 

 purpose, with its upper end protruding slightly above the 

 surface of the ground. If the earth has recently been dis- 

 turbed about the surface of the tree, so as to make it lie loose, 

 the larva will often form its cocoon an inch or more below 

 the surface. The enclosed pupa is at first white, but soon 

 becomes of a pale tawny-yellow color, with a darker ring at 

 each of the sutures of the body ; the pupa state lasts some 

 three weeks or more. 



This is an American insect, unknown on the peach-trees of 

 other countries. Its operations are not confined to the peach ; 

 it works also on the plum, although in this instance no gum 

 exudes from the tree, and it is quite probable that before the 

 introduction of the peach into this country the larva lived in 

 the roots of the wild plum, which it has now almost entirely 

 forsaken. 



13 



