86 COLEOPTERA. 



tion of new wood ; the bark becomes loosened from the wood, 

 to a greater or less extent, and the tree languishes and prema- 

 Fig. 42. turely decays. The name of this insect is Hylur- 

 9 m twebrans,* the boring Hylurgus (Fig. 42) ; the 

 generical name signifying a carpenter, or worker in 

 wood. It belongs to the family ScoLYTiDja, includ- 

 ing various kinds of destructive insects, which may be called 

 cylindrical bark-beetles. The insects of this family may be 

 recognized by the following characters. The body is nearly 

 cylindrical, obtuse before and behind, and generally of some 

 shade of brown. The head is rounded, sunk pretty deeply 

 in the fore part of the thorax, and does not end with a 

 snout ; the antennas are short, more or less crooked or curved 

 in the middle, and end with an oval knob ; the feelers are 

 very short. The thorax is rather long, and as broad as the 

 following part of the body. The wing-covers are frequently 

 cut off obliquely, or hollowed at the hinder extremity. The 

 legs are short and strong, with little teeth on the outer edge 

 or extremity of the shanks, and the feet are not wide and 

 spongy beneath. 



Though these cylindrical bark-beetles are of small size, 

 they multiply very fast, and where they abound are produc- 

 tive of much mischief, particularly in forests, which are often 

 greatly injured by their Iarva3, and the wood is rendered 

 unfit for the purposes of art. In the year 1780, an insect 

 of this family made its appearance in the pine-trees of one 

 of the mining districts of Germany, where it increased so 

 rapidly that in three years afterwards whole forests had 

 disappeared beneath its ravages, and an end was nearly put 

 to the working of the extensive mines in this range of 

 country, for the want of fuel to carry on the operations. 

 Pines and firs are the most subject to their attacks, but there 

 are some kinds which infest other trees. The premature 

 decay of the elm in some parts of Europe is occasioned by 

 the ravages of the Scolytus destructor, of which an interesting 



* Scolytus lerebrans of Olivier. 



