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FlllST BOOK OF FOKESTlfY 



only effective way of fighting them is by cutting a number 

 of '' trap trees/' This is best done by girdling or felling 

 a niiml)er of the smaller, poorer trees, about fifty yards 



^ Fig. id. Bark Beetles and their Work 



A, Galleries on a block of wood, just beneath the bark ; B, the bark beetle Tomicus ; 

 C, the bark beetle Dendroetonus. Natural size is indicated by straight line 

 between beetles 



