DOUGLAS FIR PITCH MOTH. 



15 



ered almost entirely due to moths, but thej^ were not counted. If 

 they had been counted the percentage of all other factors would not 

 have exceeded 1 per cent, and this in a location more or less unfavor- 

 able for the moth. 



CHARACTER OF LARVAL WORK. 



(Figs. 9-10.) 



If trees have been injured the eggs are evidently deposited by the 

 moth at the edge of wounds, regardless of their origin, and the larva 



p» 



0. — Tunnel at the end of (he first active season of the larvce of 

 tbe Douglas fir i)it<h moth. Natural size. (Original.) 



begins feeding at such places. The larva apparently follows the line 

 of leasf resistance, because the resulting tunnel is likely to assume any 

 shape in such mses. On perfectly sound trees the egg is evidently 

 deposited wlu^-e the bark is absolutely smooth and fresh, and the larva 

 feeds upon the bark as soon as it slips out of the eggshell. This is 

 apparently also the reason why trees with (hick hark are, attacked 

 only where sesiid or other partially healed wounds provide, condi- 

 tions which answer the same requirement. 



