WEST VIRGINIA GEOLOGICAL SURVEY. 



91 



Shavers mountain, in Randolph county. The Hickory Bark- 

 borer {Scolytus qudrispinosus Say) is a destructive enemy of 

 hickory in the region from Wisconsin to Vermont and south 

 to Georgia. Its injuries, like the others, consist of mines and 

 galleries made in the inner bark. 



Insects That Injure the Wood of Living and Dead Trees. 



One of the commonest forms of insect injury to wood con- 

 sists of pinholes or wormholes that are revealed as the logs are 

 sawed into lumber. Often a tree will have every appearance 

 externally of being sound but when it is manufactured defects 

 of this kind will be so abundant that a very large portion of 

 the lumber can be graded only as culls. Hard and soft wood 

 of all kinds are subject to these injuries and it is not infre- 

 quent for lumber to be reduced in value fully 50 per cent by 

 their occurrence. 



Several species of insects are responsible for these defects. 

 The Oak Timber Worm {Eupsalis minuta Dru.) gains access 

 to the heartwood of li^dng trees through bruises in the bark, ax 

 wounds or the bases of broken and dead limbs. From the place 

 of entrance the burrows extend in every direction through the 

 wood. Old oak trees are almost sure to contain more or less 

 of the burrows of this insect and the loss is often enormous. 

 The Chestnut Timber Worm {Lymexylon sericeum Harr.) at- 

 tacks chestnut in a manner similar to the way in which the 

 species last mentioned attacks oak. Defects in chestnut lum- 

 ber caused by this species are perhaps even more abundant 

 than are those in oak caused by the oak timber worm. Scarcely 

 a chestnut tree of merchantable size can be found that has not 

 been injured to some extent. Hopkins estimates that the re- 

 duction in value of the average chestnut lumber product due to 

 this species is not far from 30 per cent. 



Very large wormholes are frequently found in white oak 

 and red oak and occasionally in other kinds of oak. These may 

 occur at any place along the trunk of the tree but are perhaps 

 most abundant about the bases of the limbs. ]\Iost of these 

 large burrows are made by the lar^^ae of large moths which are 



