ASH-BARK BEETLE. 



199 



attacks 



The black Ash -bark beetle, H. crenatus, $ to 4 in. long, 

 trees injured by H. fraxini, and breeds there till the tree dies. 



*The 2 -toothed Pine -bark beetle, Bostrichus bidens, is the com- 

 monest Bostrichus in our woodlands. It chiefly attacks Scots Pine, but 

 also other Pines, Spruce, and Larch, its attacks being mainly confined to 

 10- or 12-year-old plantations, or to the thin-barked crowns and branches 



Fig. 42. 



Portion of youn& Ash-trunk with borings of H. fraxini, 2f nat. size, 



of poles and trees. It sometimes does extensive damage in plantations, 

 and even interrupts the canopy of old Pine-woods. 



Beetle about - X V in. long, black, glossy, and covered with fine hairs. 

 The shield- wings are usually dark-brown, with rows of fine punctures. 

 In the both shield-wings have broad, flat indentations, on the upper 

 edge of each of which there is a large, hooked, tooth-like process (hence 

 bidens} ; but the ^ has not these indentations and tooth-like processes. 

 Beetles appear in May and June, and lay eggs on the thin bark of young 



