316 INSECTS AFFECTING VEGETATION 



roundheaded wood borers, which hatch from eggs deposited in the 

 bark before or after the lumber is sawed. There are examples of 

 losses from this character of injury amounting to from 20 to 50 per 

 cent or more. Telegraph and telephone poles, posts, mine props, 

 etc., are frequently injured before they are set in the ground, espe- 

 cially if the bark remains on them during a few weeks after the 

 middle of March. 



SEASONED PRODUCTS IN YARDS AND STOREHOUSES. 



Powder-Post Beetles.* Hardwood lumber of all kinds, rough 

 handles, wagon stock, etc., made partially or entirely of sapwood, 

 are often reduced in value from 10 to 90 per cent by a class of insects 

 known as powder-post beetles. The sapwood of hickory, ash, and 

 oak is most liable to attack. The reported losses from this source dur- 

 ing the past five or six years indicate that there has been an average 

 reduction in values of from 5 to 10 per cent or more. Old hemlock 

 and oak tanbark is often so badly damaged by various insects which 

 infest dead and dry bark that in some tanyards as much as 50 to 75 

 per cent of the bark that is over three years old is destroyed. In one 

 tannery in West Virginia it is estimated that more than $30,000 

 worth of hemlock bark was thus destroyed. 



FINISHED PRODUCTS. 



The greatest loss of finished hardwood products, such as handle, 

 wagon, carriage, and machinery stock is caused by powder-post 

 beetles. This is especially true of hickory and ash handles and like 

 products in the large and small storehouses of the country, including 

 the vast amount of material held in storage for the army and navy. 

 When material of this kind is once attacked it is usually worthless 

 for the purposes indicated, and therefore must be replaced with new 

 material. In some cases losses have amounted to from 10 to 50 per 

 cent, and it is estimated that the average losses have been as much as 

 10 per cent on nearly all sapwood material that has been in storage 

 more than one year. 



UTILIZED PRODUCTS. 



Powder-Post Beetles, White Ants, and Other Wood-Boring In- 

 sects. The finished woodwork in implements, machinery, wagons, 

 furniture, and the inside finish in private and public buildings are 

 often seriously damaged by powder-post beetles, thus requiring in- 

 creased demands for new material. 



Construction timbers and other woodwork in new and old build- 

 ings are often so seriously damaged by powder-post beetles, white 

 ants, and other wood-boring insects that the affected material has to 

 be removed and replaced by new, or the entire structure torn down 

 and rebuilt. Construction timbers in bridges and like structures, 

 railroad ties, telephone and telegraph poles, mine props, fence posts, 

 etc., are sometimes seriously injured by wood-boring larvae, termites, 

 black ants, carpenter bees, and powder-post beetles, and sometimes 

 reduced in efficiency from 10 to 100 per cent. 



INSECTS AND THE FUTURE SUPPLIES OF TIMBER. 



Insects not only reduce future supplies by killing the mature 

 trees and destroying the wood of timber that is inaccessible for utili- 



*See illustration on page 663. 



