INSECT ENEMIES OF WESTERN FORESTS 



117 



shows three or four egg galleries forking from a central nuptial 

 chamber and running more or less longitudinally with the grain 

 of the Avood for a distance of 5 to 10 inches. There may be any- 

 wdiere from one to seven females to each male, with as many egg 

 galleries radiating from the one nuptial chamber. There are from 

 two to four generations of this species a year, depending on the 

 locality and the length of season. The parent adults often emerge 

 and make a second and even a third attack that results in a con- 

 fusing overlapping of 

 broods. Preventing 

 these beetles from be- 

 coming too numerous 

 through timely slash 

 disposal will do more 

 to prevent damage 

 than the application of 

 control measures after 

 damage has occurred. 

 The Monterey pine 

 engraver {Ips radiatae 

 Hopk.) attacks living, 

 injured, dying, and re- 

 cently felled Monterey, 

 Bishop, knobcone, Jef- 

 frey, lodgepole, and 

 whitebark pines from 

 central California 

 northward to British 

 Columbia and east- 

 ward to Idaho and 

 Wyoming. It is usu- 

 ally a secondary enemy 

 and associated w i t h 

 other bark beetles in 

 its attack, but at times 

 may become primary, especially in plantations of Monterey pine. 

 The adult beetles are about one-fifth of an inch in length, dark brown 

 and shining, with parallel sides and one very prominent spine on the 

 end of each wing cover. The ^gg galleries are curved or S-shaped, 

 with three or four larval mines issuing from each Qgg pocket (fig. 57). 

 The rapidity of development and the number of generations will 

 vary with different seasons and localities. Usually there are one or 

 two summer generations and an overw^intering generation. The 

 beetles overwinter beneath the bark of trees killed during the pre- 

 vious summer, mostly as adults, but also as larvae and pupae. Some 

 extensive control operations have been undertaken in California to 

 suppress outbreaks of this beetle that developed from roadway 

 slashings. 



Pityogenes and other wood engraver ~beetJes 



The small bark beetles belonging to the genus Pityogenes are 

 sometimes referred to as "wood engravers." They usually are of 

 secondary importance and attack the tops, limbs, and twigs, of 



riGUPE 



pine engiavei 



radiatae) . 



Adult ( X 8) and pattern ot woik on sapwood 



