4 BULLETIN 111, IT. S. DEPARTMENT OF AGRICULTURE. 
1-year-old larvae were abundant. If this observation holds good, 
the insect being biennial, we should be able to forecast the years 
when it will be abundant and when scarce. Hence there should be 
great nights during 1914, 1916, 1918, etc., unless the insect is con- 
trolled, and small flights during 1915, 1917, 1919, etc, 
RELATION TO THE MOUNTAIN PINE BEETLE. 
The only insect which is of any consequence in its relation to the 
pitch moth in the Clearwater country is Dendroctonus monticolae 
Hopk. This beetle frequently attacks trees infested by the larvae 
of the moth. This attack is always fatal to the latter, because 
Dendroctonus kills the tree almost immediately, and without the flow 
of sap the larvae of the moth can not survive. On October 1 every 
larva of the moth which was found in trees attacked by the beetle 
after August 1 was dead. Some of the trees had the appearance of 
having been infested by the beetle only two or three weeks; never- 
theless, the moth larvse were dead, although they were in perfectly 
fresh condition otherwise. 
Vespamima sequoia is apparently little subject to attack by either 
parasitic or predaceous enemies. In fact, it is less troubled by insect 
enemies or diseases than any other species known to the writer; and 
as birds also never seem to pursue it, there is no present evidence 
that natural agencies might check it in the course of time. 
HABITAT. 
The insect prefers sunny openings within the forest and slopes 
where the soil is rather sandy and quick to dry. Ridges along 
watercourses are also favorite places for it. It avoids the damp and 
densely shaded bottom lands along streams. It prefers pine, open 
stands of lodgepole pine, as, for example, within and alongside the 
big old burn which extends from the wagon road toward and along 
the Flathead Range, where there are few trees 3 or more inches in 
diameter that have escaped attack and are not infested now. 
HOST TREES, AND CHARACTER OF INJURY. 
Lodgepole pine is numerically the principal species of tree in the 
region and, with the rare exception of the yellow pine, is the species 
subject to attack by the pitch moth, although the moth attacks 
almost all kinds of conifers in other localities within its range. 
The trees infested by this insect (see fig. 2) are readily located by 
the never-absent pitch exudation over the tunnel of the larva. This 
may be readily seen at quite a distance, if the stand of trees is not 
too young. Even on very small trees of but 1 or 2 inches in diameter 
the pitch tube is of the size of a walnut the first season of the infesta- 
tion and more than twice that the second year. 
The pitch exudation on the tree shown in figure 3 weighed over 
10 pounds, and such trees are so numerous that many tons of pitch 
