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used in railroad construction, such as ties and culvert, bridge, and 

 trestling timbers. This insect will breed in old oak logs as long as 

 there is suificient amount of sound wood for it to work in, and under 

 favorable conditions it will doubtless do the same in railroad ties and 

 other similar material which comes in connection with the ground. 



The chestnut timber worm {Lymexylon sericeum) is another exceed- 

 ingly destructive insect to the wood of living, dying, and dead oak 

 trees, stumps, logs, and heavy construction timbers as long as the con- 

 ditions are suitable for it to do so. The destruction of the wood of 

 old chestnut trees throughout the Appalachian region, so far as its 

 value for construction material is concerned, is well-nigh complete. 

 Otherwise this durable and valuable timber would be a good substi- 

 tute for the rapidly diminishing oak, and on account of its rapid 

 growth from a young sprout to a tree of commercial size would be a 

 most profitable forest tree to grow for future supplies. 



The giant root borer {Prionus laticollis) is another enemy of wood 

 which not only breeds in the roots and stems of living oak and other 

 timber trees, but in old stumps and logs, railroad and other timbers 

 which, owing to their connection with the ground, retain a sufficient 

 amount of moisture. Some years ago I observed a large number of 

 larv?e, apparently of this species, in some old oak railroad ties which 

 were being removed from the roadbed in front of the Baltimore and 

 Ohio station in Morgantown. It is therefore evident that this class 

 of large wood borers contribute not a little to the rapid deterioration 

 of oak ties and other timbers. 



There is another class of Cerambycid, or round-headed borers, of 

 the Centrodera, Leptura, and other allied genera, which breed in the 

 wood of dead trees and logs, hence are capable of breeding in railroad 

 ties and similar construction material. There are also many species 

 in the family Buprestid?e with similar habit. In the Scolytidse there 

 are large numbers of species which bore in the wood of living, dying, 

 and dead trees and cause serious defects. Indeed, there is a long list 

 of species of Coleoptera which bore in the wood of trees and construc- 

 tion timbers and contribute to rapid deterioration and decay. 



In Lepidoptera there are some very destructive enemies of the wood 

 of living trees, notably the carpenter worms, which infest the oak and 

 locust and bore large holes through the best part of the wood. 



In Hymenoptera there are certain wood-boring bees and ants which 

 do great harm to the timber and other woodwork of buildings, bridges, 

 and railroads. 



In Neuroptera the termites are among the most destructive enemies 

 of wood and of wooden structures, working both in the moist and 

 sound wood. Recently the writer has determined that these so-called 

 white ants are very injurious to railroad ties and other railroad timbers. 



Thus a great variety of insects are to blame for defective timber. 

 They attack the dead, living, and felled trees, the rough manufac- 

 tured product in the mill yards before it is used, after it is used in the 



