INSECT ENEMIES OF WESTERN FORESTS cy, 
shows three or four egg galleries forking from a central nuptial 
chamber and running more or less longitudinally with the grain 
of the wood for a distance of 5 to 10 inches. There may be any- 
where 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 U4: 
these beetles from be- Ny Vaal 
coming too numerous NUN 
through timely slash 
disposal will do more 
to prevent damage 
than the application of 
control measures after 
damage has occurred. 
The Monterey pine 
eneraver (Jps radiatae  |I% 
Hopk.) attacks living, | Swag 
injured, dying, and re- ie 
cently felled Monterey, ne 
Bishop, knobcone, Jef- ia q 
frey, lodgepole, and tie 
Nati 
tl 
whitebark pines from | Pee 
central California |f 15 DY” 
northward to British &fity:/¢ Ail k 
Columbia and east- || ee bi 
ward to Tdaho and “WHR Wy pay Z ‘fh 
Wyoming.. It is usu- Hi Wie ae ial it : 
ally a secondary enemy [HIN )3, 2400 UG : 
and associated with Z snk ae . ey 
. TIGURE 57.—Monterey pine engraver (Ips radiatae) : 
other bark beetles in Adult (X 8) and pattern of work on sapwood. 
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 egg galleries are curved or S-shaped, 
with three or four larval mines issuing from each egg 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 overwintering 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 beetles 
The small bark beetles belonging to the genus Pétyogenes are 
sometimes referred to as “wood engravers.” They usually are of 
secondary importance and attack the tops, limbs, and twigs, of 
