THE POWDER POST BEETLE 121 
destroying the timbers in a bridge* As he leaves no 
external marks of his operations except the fine brown 
powder he scatters about and the pin-holes through 
which he enters and emerges, the weakened condition 
of the wood he has perforated is not readily discerned* 
A slender Beetle, less than a quarter of an inch 
long, can penetrate rough or even finished hardwood 
without leaving any conspicuous marks* The eggs 
are laid in the wood, and when the minute white 
grubs are hatched they burrow in and through the 
wood in all directions, feeding and growing until 
ready for the inert sleep of the pupa stage. For this 
transformation each diminutive grub forms a cell 
at the end of its burrow. When its legs and wings 
are fully developed it awakes to new life and bores 
its way out, a perfect beetle ready to transmit the 
destructive life it has inherited. The dry, hard 
woodwork of carriages, the handles of tools, the 
material of finished interiors, old furniture, hard- 
wood floors, joists, and frames are the strangely 
acceptable diet of this dangerous intruder. But he 
fortunately confines himself almost exclusively to the 
sap wood. All wood from the heart of the tree is 
virtually safe. With our abundance of hardwood there 
is no excuse for using the vulnerable part and thus 
providing costly food and lodging for this pest. If 
we are sufficiently parsimonious or dishonest to use 
sap wood we will be courting punishment. 
