[900. 



AMERICAN FORESTRY ASSOCIATION. 



53 



The form of their burrows is quite char- 

 acteristic. They first bore a round hole 

 through the bark to the surface of the wood, 

 then cut a burrow three or four inches 

 long up and down the tree, in which the 

 sexes mate and in the edges of which the 

 eggs are laid. The borings meanwhile 

 are thrown out of the burrow, and pitchy 

 as they are often form a tube, which 

 marks the infected tree. The larvas when 

 hatched bore out laterally in the soft tissue 

 between the solid wood and bark, eating out 

 a channel which increases in dimensions as 

 the insect grows. Finally thegrub pupates 

 and after reaching the adult form works its 

 way free. The winter is passed in all three 

 stages. The indications are that more than 

 one generation is passed in a year.* 



Ordinarily, as noted above, great num- 

 bers of beetles attack a tree together and, 

 when the colonies of larvaB are well grown, 

 their work completely girdles it. The 

 leaves then drop off, leaving the tree con- 

 spicuous by its red appearance. Year by 

 year after that the twigs and limbs drop 

 off. The trunk of the tree also shows 

 quick depreciation. Ordinarily the sap 

 wood begins to show signs of decay within 

 a few months. The heart wood is much 

 slower to follow, but from all that has 

 been seen it appears probable that there is 

 in the run a lessening of something like 

 fifty per cent, in available lumber within 

 two years after the death of the timber. 

 Wood boring insects assist decay in the 

 process of destruction. On the other 

 hand, woodpeckers often considerably 

 postpone it by loosening the bark so that 

 water does not stand under it. 



As to choice of trees and of stands the 

 following can be said. The beetle with 

 us is working on apparently vigorous, 

 though large and old, timber. It attacks 

 both black and white Spruce, but so far 

 as noted no other species. Its choice is 

 the very largest and finest timber, not 

 necessarily the thickest. Stands of smaller 

 sized Spruce, cut-over lands, and trees 

 below twelve or fourteen inches in breast 

 diameter, are usually exempt. The free- 



* Mr. W. F. Fiske, of the Experiment Station 

 at Dunham, N. H., is entitled to the credit of 

 working out some of these points. 



dom of the younger Spruce is in accordance 

 with general principles relating to such 

 things, but the exact cause for it is not so 

 evident. In this connection it has been 

 suggested by things seen that the flow of 

 pitch perhaps was too strong for the 

 beetles in the younger timber. Beetles 

 that have apparently been drowned by the 

 flow of pitch into their burrows are some- 

 times found, and examples are not absent 

 of trees which have resisted attack and are 

 now 7 covering over the scars then made. 



A pamphlet of great interest in this con- 

 nection is Bulletin 56 of the West Virginia 

 Experiment Station, containing the results 

 of Professor A. D. Hopkins' study of in- 

 sect depredations on the Spruce and Pine 

 forests of that state within the last eighteen 

 yeats. This work, dealing as it does not 

 only with the cause of the trouble but 

 with secondary problems also, and sug- 

 gesting means of alleviation as well, \vill 

 be an aid to clear thinking on any similar 

 problem. It is a mark of progress that 

 one such problem in the United States has 

 at length received something like the atten- 

 tion which its importance deserves. 



When the loss we are suffering in Maine 

 was first discovered, when the cause of it 

 was identified and found to be one capable 

 of further extensive destruction, when 

 alongside the freshness of the work of the 

 beetles it was found by a season's cruising 

 that they were distributed throughout the 

 Androscoggin drainage and at work further 

 east than Moosehead Lake in central 

 Maine, the suggestion at once arose that 

 we might have in this insect a serious 

 threat to the welfare of our Spruce forests, 

 forests of vast importance to the business 

 interests of the New England States. The 

 idea was very stimulative of effort. For 

 two and a-half years the matter has been 

 watched as closely as it could be watched 

 by one not an entomologist and with many 

 other duties to perform. Other men have 

 been put on their guard, and the regula- 

 tion of cutting, so as to offset the damage 

 done, has been suggested to those with 

 whom the writer has had influence. A 

 constant source of regret has been that no 

 entomologist could be induced to give the 

 matter careful and continued attention. 





