INSECT ENEMIES OF WESTERN FORESTS 



177 



Figure 82. — The Yosemite bark weevil (Pissodes yosemite Hopk.) : A, Typical 

 work; B, adults. Slightly enlarged. 



is oval in outline and is lined with excelsiorlike shreds of wood 

 fiber. The nearly round larval mines and the "chip cocoons" are 

 characteristic features of their work. 



The adults are long lived and may deposit their eggs over a con- 

 siderable period of time. The larvae, which reach maturity rapidly, 

 usually within 2 or 3 months, may overwinter in the galleries or 

 transform to adults that either overwinter under the bark or 

 emerge and hibernate in the ground. There usually is but one 

 generation annually. 



Artificial control of the species in western forests has never been 

 found necessary, as they are usually held in check by natural ene- 

 mies and the limitation of suitable breeding material. 



Bark weevils of the genus Pissodes that are most commonly 

 found breeding under the thick bark at the base of small conifers, 

 and the hosts in which they breed are as follows : 



