112 MISC. PUBLICATION 273, U. 8S. DEPT. OF AGRICULTURE 
so much as does the lack of suitable host material. Given a quantity 
of freshly cut slash or windfalls, a large beetle population is 
almost certain to be produced but it will not long survive after 
the supply of this material is exhausted. 
Since outbreaks in standing, healthy trees are sporadic and of short 
duration, the destruction of the broods in these trees, through the 
application of control methods, seldom contributes a great deal 
toward reducing the damage. Efforts should be directed toward 
preventing outbreaks by eliminating all situations favorable to the 
development of excessive progeny. Thus, slash should be piled and 
burned before the /ps beetles emerge, or scattered in the open where 
the sun will dry it out and make it unsuitable as a breeding medium. 
If it should be necessary to destroy broods in standing trees, the most 
economical and effective method is to fell the trees and burn or scorch 
the infested bark. A large number of species of this genus are 
recorded from western pines, all very similar in appearance and 
naps, so only a few of the more common species need be mentioned 
1ere. 
The western six-spined engraver (/ps ponderosae Sw.) is a second- 
ary enemy of ponderosa pine, which for the most part attacks trees 
that have been felled or those dying from attacks of more primary 
species of bark beetles. The adults are about one-fourth inch in 
length, reddish brown to black, with six spines on each side of the 
elytral declivity. The gallery pattern consists of from two to five 
ege@ galleries extending up and down the tree from the central nuptial 
chamber. Though the pattern is similar to that of 7. oregoni, the 
galleries are distinctly wider. This beetle has been recorded from 
Arizona, California, Montana, and South Dakota, and undoubtedly is 
present in other Western States. 
The California five-spined engraver (/ps confusus Lec.) is destruc- 
tive to tops of mature trees, small poles, and the saplings of various 
pines in California and southern Oregon west of the Cascade and 
Sierra Nevada ranges. It breeds readily in slash and felled logs, and 
the broods from such material often cause extensive damage to the 
young pine growth in the vicinity. It commonly attacks ponderosa 
pine, sugar pine, western white pine, Coulter pine, Monterey pine, 
and less frequently other pines within its range. 
The adults are reddish brown to pitch black, about one-eighth inch 
long and with five spines on the margin of each side of the elytral 
declivity. The egg galleries usually comprise from three to five 
nearly straight tunnels radiating from a central entrance chamber. 
The typical form has three galleries in the shape of an inverted Y. 
These galleries are not packed with boring dust and are usually from 
5 to 10 inches long. Attacks are started early in the spring and from 
two to five generations of beetles may develop during the summer. 
In the northern part of the range, at an elevation of about 3,000 feet, 
there are usually two summer generations which develop in fallen 
logs and a third, or overwintering generation, which develops in 
standing trees. At lower altitudes and in the southern part of the 
range there are from three to five summer generations. The beetles 
overwinter mostly in the adult stage, under the bark of recently killed 
trees and probably in crevices and under litter on the ground. 
