DOUGLAS FIR PITCH MOTH. 15 
ered almost entirely due to moths, but they 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 
Fic. 9.—Tunnel at the end of the first active season of the larvez of 
the Douglas fir pitch moth, Natural size. (Original.) 
begins feeding at such places. The larva apparently follows the line 
of least resistance, because the resulting tunnel is likely to assume any 
shape in such cases. On perfectly sound trees the egg is evidently 
deposited where the bark is absolutely smooth and fresh, and the larv: 
feeds upon the bark as soon as it slips out of the eggshell. This is 
apparently also the reason why trees with thick bark are attacked 
only where sesiid or other partially healed wounds provide condi- 
tions which answer the same requirement. 
