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 excltxsively 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 sufl&dently parsimonious or dishonest to use 

 sap wood we will be courting punishment. 



