248 



WEST VIRGINIA EXPERIMENT STATION. 



bark, where a broad cavity is excavated which is utilized as a 

 nuptial chamber. In the meantime, the female, which appears 

 to do the greater part of the first excavating, is joined by a 

 male which stations himself in the entrance gallery to keep 

 out enemies and objectionable visitors, and to render assistance 

 in expelling the borings. The female then excavates a gallery 

 from one edge of the nuptial chamber through the inner bark 

 to the wood, thence through the inner layer of bark, usually at 

 right angles to the bark fibers, for a distance of one or two 

 inches. Along the sides of this so-called brood or egg-gallery, 

 she deposits her minute, pearly-white eggs in a succession of 

 small notches. By the time the first female has her egg gallery 

 iairly started, one to three other females are admitted, and 

 each excavates a similar egg gallery in different directions from 

 the nuptial chamber. Before all of the galleries are finished, 

 the first egg commences to hatch into minute white grubs, 

 which burrow through the inner bark, on which they feed. By 

 the time all of the eggs have hatched, the surrounding bark is 

 filled with these grubs of various ages and sizes, and soon, all 



of the bark from the inner to the outer 

 layer, for a radius of two to four inches, 

 is completely perforated with their 

 irregular burrows. In the meantime, 

 the male guards the entrance and the 

 females either rest in the nuptial cham- 

 ber or egg galleries, or emerge to enter 

 the bark in another place to start a new 

 brood. When the grubs and larvae 

 have attained their full growth, they 

 excavate a broader cavity at the end 

 of their burrow or mine, in which they 

 change to the pupae stage, thence to 

 the adult and either emerge from the 



Fig. XXV.-Chip from Black bark 3nd Start * SeCOnd br d > F r6 ' 



^ P io^oVblrkandi n x g it d hoies C " main tnere unti l tne following spring. 

 m ^runpenlT phU8 Probably two or three broods may 



