INSECTS AFFECTING PAKK AND WOODLAND TREES 



587 



Description. Tlu' bc'ctlc varirs from a light brown to a black. It is 

 quite small, being about ' ,.. inch long and with a rather stout form. The 

 heail is thickl)- and fmeh- puncturi'd and nearly concealed by the overhang- 

 ing prothorax. The mouth parts are lippeil with black and the concolorous, 

 coarsely granulated eyes are di\ided, the two portions being connected by 

 a smooth strip of chitin. The prothorax is much narrowed in front, thickly 

 antl finely punctured anil the wing covers or elytra are rough, finely 

 punctured and almost striate'. The structure of the antennae is shown on 

 plate 67, figure cS, and that of the lil)ia in figure S^a . 



The white pupa is about the same size as the beetle, rather stout 

 and witli a tapering abdomen terminated by a pair of fleshy spinelike 

 processes. 



The brown headed, white grubs or larvae are about ^ inch long 

 when full grown. The mouth parts and adjacent sutures are a dark brown 

 and the body is usualh' somewhat curved. 



Life history. The life history of this borer in West Virginia has been 



given by I)r Hopkins as follows : 



The adults emerge in May or June and are attracted to stumps, trunks 

 and tops of recently fallen trees and those that are weakened by the attack 

 of insects, such as the destructive pine bark beetle, Dendroctonus 

 frontalis Zimm., or diseases of any kinds. The .beetles commence to 

 excavate entrance galleries through the outer bark, and their presence is 

 indicated by the fine brownish borings in the crevices of the bark. This 

 entrance is extended to the outer surface of the inner soft bark where the 

 central chamber is excavated. In the meantime, the 

 female, which appears to do the greater part of the 

 work, is joined by a male" who stations himself in the 

 outer gallery to keep out enemies and objectionable 

 visitors and to render assistance in expelling the bor- 

 ings. The female excavates a gallery from one edge 

 of the central chamber through the inner bark of the 

 wood and then in the inner layer of the bark, usually 

 at right angles to the bark fibers, and for a distance 

 Fig. 86 Poiyeraphus rufi- of oue Or two iuches. Small notches are made along 



pe n n is : early galleries and eeg ^1 • 1 r ^1 1 l 11 • 1 r 1 . 1 1 



notc!,eWauthnr-.iiiustrntioni the sides ot thc brood gallery, in each of which pearly 



white eggs are deposited. One to three other females 



are admitted to this central chamber by the male and from it extend similar 



