INSECT ENEMIES OF WESTERN FORESTS 153 



which breeds in ponderosa, lodgepole, white-bark, Jeffrey, and 

 probably other pines and is distributed over nearly all the West- 

 ern States. The females have three small, spinelike teeth along 

 each margin of the elytral declivity, whereas the males have only 

 two declivital teeth on each side, the first pair strongly developed 

 into prominently curved spines. Their gallery pattern consists of 

 8 to 10 or more rather slender egg galleries from 1 to 2 inches 

 long, radiating from a circular entrance chamber. 



Pityogenes knechteli Sw. is a slender species similar to the 

 above, commonly found associated with Ips and Dendroctonus 

 beetles under the thin bark of lodgepole and other pines in the 

 Western States and in British Columbia, and is sometimes respon- 

 sible for the destruction of small patches of lodgepole pine repro- 

 duction. The work consists of three to five egg galleries iy 2 to 3 

 inches long, radiating from the central nuptial chamber. 



Pityogenes fossifrons (Lee.) is a brownish-black species occa- 

 sionally found working in the tops and limbs of weakened or dying 

 western white, whitebark, limber, lodgepole, and other pines from 

 California northward to British Columbia and eastward to Idaho. 

 Its attacks are seldom primary, although it sometimes attacks 

 western white pine reproduction. The adults have three very small 

 spines along each margin of the elytral declivity, somewhat larger 

 in the males. Their gallery pattern consists of four to six egg 

 tunnels 1 to l 1 ^ inches long, radiating from the entrance or nuptial 

 chamber (fig. 70). 



'• — *rs 



Figure 70. — Typical galleries and egg niches of Pityogenes fossifrons. 



Several other species of small engraver beetles may be encoun- 

 tered under the bark of pines. Orthotomicus ornatus Sw. is a 

 small species about % inch long, closely resembling a small Ips. 

 The elytral declivity is slightly concave, with three pairs of small 



