100 MISC. PUBLICATION 273, U. 8. DEPT. OF AGRICULTURE 
Direct control is recommended, particularly during developing epi- 
demic conditions. The control measures consist in felling the infested 
trees; peeling and burning the bark late in the fall, or in winter or 
early spring; or peeling and spreading the bark for destruction of 
Figure 48.—Work of the western pine beetle (Dendroctonus brevicomis): A, Egg galler- 
ies on inner bark (half size) ; B, an infested tree trunk with bark removed (drawing 
by DeYoung) ; C, 1 year’s loss in a ponderosa pine stand in California. 
the broods by solar heat during the summer months. Control work 
has been successful in reducing infestations during critical periods, 
but cannot be relied on to eliminate them, and must be repeated until 
natural control factors become operative. 
The southwestern pine beetle (Dentroctonus barberi Hopk.) attacks 
ponderosa pines in southern Colorado, southern Utah, Arizona, and 
New Mexico. A preference is shown for trees over 6 inches in diam- 
