266 NATURAL HISTORY. [CH. XIX. 



CHAPTER XIX. 



NATURAL HISTORY OF SOME INSECTS WHICH ARE OBNOX- 

 IOUS TO TREES. 



History of the Larva which is termed the Oak-pruner — History of 

 he Larva which causes Tumours on Fruit-trees — History of 

 Hylesinus Destructor — History of the brown-tailed Moth. 



Some insects cause very great mischief to trees, 

 many of which are peculiarly infested by certain 

 kinds. Of such magnitude are the ravages some- 

 times committed, that whole forests have been de- 

 stroyed by them ; therefore it becomes necessary 

 for man to exert his best endeavours to stop the 

 progress of such an evil. Before he can accomplish 

 this object, he must make himself well acquainted 

 with the peculiar modes of life of the insect or in- 

 sects which have thus attacked them ; and perhaps 

 the history of several may not prove uninteresting 

 to the general reader. 



For several years past, the ground beneath the 

 black and white oaks of America has been observed 

 to be strewed with small branches of those trees 

 from eighteen inches to two feet in length. Some 

 of them have been found five feet in length and an 

 inch in diameter. The falling of these branches is 

 occasioned by the larva or grub of an insect, which, 

 from this effect of its labour, may be called the oak- 

 pruner. When its feeding or larva state is nearly 

 complete, it eats away the wood in a circular direc- 

 tion, leaving only the bark entire ; this is broken by 

 the first strong breeze, and the branch, with the 

 larvae in it, falls to the ground. Several branches ; 

 containing larvae were placed in a vessel covered 

 with a piece of window-glass to prevent the escape 



