42 INSECTS INJURIOUS TO VEGETATION. 



verse ; next to it is a large, oval segment, broader than long, and 

 depressed or flattened above and beneath. Behind this, the seg- 

 ments are very much narrowed, and become gradually longer ; 

 but are still flattened, to the last, which is terminated by a round- 

 ed tubercle or wart. There are no legs, nor any apparatus which 

 can serve as such, except two small warts on the under-side of 

 the second segment from the thorax. The motion of the grub 

 appears to be effected by the alternate contractions and elonga- 

 tions of the segments, aided, perhaps, by the tubercular extremity 

 of the body, and by its jaws, with which it takes hold of the sides 

 of its burrow, and thus draws itself along. These grubs are found 

 under the bark and in the solid wood of trees, and sometimes in 

 great numbers. They frequently rest with the body bent side- 

 wise, so that the head and tail approach each other. This pos- 

 ture those found under bark usually assume. They appear to 

 pass several years in the larva state. The pupa bears a near re- 

 semblance to the perfect insect, but is entirely white, until near 

 the time of its last transformation. Its situation is immediately 

 under the bark, the head being directed outwards, so that when 

 the pupa-coat is cast off, the beetle has merely a thin covering of 

 bark to perforate, before making its escape from the tree. The 

 form of this perforation is oval, as is also a transverse section of 

 the burrow, that shape being best adapted to the form, motions, 

 and egress of the insect. 



Some of these beetles are known to eat leaves and flowers, and 

 of this nature is probably the food of all of them. The injury 

 they may thus commit is not very apparent, and cannot bear any 

 comparison with the extensive ravages of their larvae. The solid 

 trunks and limbs of sound and vigorous trees are often bored 

 through in various directions by these insects, which, during a 

 long-continued life, derive their only nourishment from the woody 

 fragments they devour. Pines and firs seem particularly subject 

 to their attacks, but other forest-trees do not escape, and even 

 fruit-trees are frequently injured by these borers. The means 

 to be used for destroying them are similar to those employ- 

 ed against other borers, and will be explained in a subsequent 

 part of this essay. It may not be amiss, however, here to 

 remark, that wood-peckers are much more successful in discover- 



