224 GEOLOGICAL SURVEY OF NEW JERSEY. 



pedes, the predatory and vegetarian types, find here both shelter 

 and food, while sow-bugs {Oniscus) are found in the lower tiers. 



The bark slippers, when they have attained their full size, eat 

 a short distance into the wood to form a pupal chamber, whose 

 entrance they plug up with shavings until they have reached 

 the adult stage. Where tan-bark is made, these same species 

 sometimes do considerable mischief, boring in the bark itself or 

 between the layers, lessening its value and occasionally ruining 

 it where left out-doors too long. 



No wood can be too hard, too dry or too dead to secure it 

 against borer attack, though its condition may often retard their 



figure 9. — A " bark slipper/' Phymatodes sp., in all stages — larva, pupa above and below, 



and adult. 



development. Larvae that live in concealment and grow slowly, 

 requiring two or three years to reach a stage which other insects 

 attain in as many months, may, under favorable conditions, have 

 their development greatly retarded. Logs may, be cut up into 

 boards, made into furniture, and come into daily use without 

 harming the contained borers, some of which have lived for 

 more than a decade under such conditions. 



In March, 1898, the yellow-pine wain.scoting of a building in 

 Somerville was found to be filled with round-headed borers. It 

 had been in place five years, and, when discovered, the insects 



