20 



EVIDENCE OF THE WORK OF THE BEETLE ON OLD DEAD TREES. 



After the trees have been dead many years most of them decay at 

 the base and fall, while the main trunks or snags of others remain 

 standing; yet as long as the surface of the wood remains sound the 

 characteristic longitudinal gallery grooves will be more or less distinct, 

 and serve to indicate that the trees were attacked while living. Pieces 

 of the old bark will also usually show traces of the galleries and indi- 

 cate by the pitch-preserved tissue that the galleries were excavated in 

 living bark. Traces of the pitch tubes may also remain on the outer 

 bark for many years and serve to indicate the cause of the trouble. 



RELATION OF WOOD-BORING INSECTS AND WOOD-DESTROYING 

 FUNGI TO THE RAPID DETERIORATION OF THE WOOD. 



As previously indicated, there are a number of wood-boring insects 

 which bore into the sapwood of dying and dead trees. Some also 

 penetrate the heartwood. Some of these wood-infesting insects enter 

 the wood as soon as the tree commences to die, others after it is dead, 

 and still others at different stages of the decline and decay as long as 

 there is anything left for them to work in. It is only those, however, 

 that enter the wood while it is yet of value for commercial purposes 

 that need to be specially mentioned in this connection. Next to the 

 one that makes the primary attack, those borers which enter the sound 

 wood are probably of the greatest importance. They not only cause 

 pin-hole and wormhole defects, which depreciate the value of the lum- 

 ber and other products into which the wood of the dying and dead 

 trees may be converted, but they give entrance to wood-decaying fungi, 

 causing rapid decay of the wood of the standing trees which would 

 otherwise remain sound for a much longer period. 



While the injuries by these wood-boring insects are by no means as 

 common where there are a great many dead and dying trees as where 

 there are only a few, it was found to be sufficient in some sections to 

 cause, in connection with the wood-deca} T ing fungi, a worthless condi- 

 tion of the timber over large areas. Indeed, it would seem from such 

 observations as we were able to make that unless the trees are cut 

 and converted into lumber, ties, cordwood, or other commercial prod- 

 ucts within two or three years after they commence to die, very little 

 of value is left. 



SUGGESTIONS FOR PREVENTING LOSSES. 



The limited time devoted to the study of this new insect was not 

 sufficient to determine the details in its life history and habits which 

 are usually so necessary in the consideration of remedies, but some 

 general features were noted, which, in connection with the information 

 acquired from special investigations of the closely related destructive 



