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THE SCOLYTID BEETLES. 
SEASONAL HISTORY. 
OVERWINTERING STAGES. 
The winter is passed in the bark on trees attacked the previous 
summer, as parent adults, larvse, and developed broods of young 
adults. 
ACTIVITY OF OVERWINTERED BROODS. 
The spring activity of the overwintered broods appears to be similar 
to that of species 9 and 10. It appears that the overwintered broods 
begin to emerge from the dying trees toward the last of July, and to 
enter the bark of other trees to excavate their galleries and deposit 
eggs, but many, and perhaps the majority, of the overwintered broods 
Fig. 61. — The Jeffrey pine beetle: Distribution map. (Author's illustration.) 
do not emerge until after the middle of August. Some of the broods 
of the first generation probably develop before cold weather, but it is 
not likely that any of them emerge before the following July. 
HABITS. 
The habits of this beetle appear to be quite similar to those of the 
mountain pine and Black Hills beetles. Therefore, while the details 
of its seasonal history and habits remain to be worked out, enough is 
known to show that it is a dangerous enemy of the Jeffrey and yellow 
pine, and that it will in all probability attack other pines within its 
range. Since the above was written the insect has been found to 
be quite destructive to the Jeffrey and western yellow pine in northern 
California. 
