150 MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



Blkm. is a closely related form which attacks lodgepole and other 

 pines in Colorado and the central Rocky Mountain region. 



The sawtooth pine engraver (Ips integer Eichh.) is distributed 

 throughout the Western States, but is most common in the Rocky 

 Mountain region. It generally breeds in weakened or felled pon- 

 derosa, lodgepole, western white, and limber pines, and western 

 larch, but under favorable conditions it may become primary. The 

 stout, brownish-black adults are about 1 5 inch long and have four 

 spinelike teeth along the margin on each side of the concave 

 elytral declivity. This species constructs three or four straight 

 longitudinal egg galleries that fork from the common entrance or 

 nuptial chamber. The egg niches are so thickly and evenly spaced 

 along the sides of the egg galleries as to give these a sawtoothed 

 appearance — a distinctive feature of this species' work. 



The California pine engraver (Ips plastographus Lee.) is a spe- 

 cies, closely related to /. integer, which prefers to attack the 

 trunks and branches of felled Monterey, Bishop, and lodgepole 

 pines, but at times also attacks weakened or dying standing trees. 

 It is not often primary in its attacks, but is usually associated with 

 the Monterey pine engraver and the red turpentine beetle in the 

 killing of living trees or trees injured by fire or other causes. It 

 is found through the range of its host trees in the coastal belt of 

 middle California and in the Sierras. The adults are about 1 ' 5 inch 

 long, with four pairs of spines on the posterior margin of the 

 wing covers. The work pattern is very similar to that of /. con- 

 fusus, the typical form having three egg galleries from 5 to 15 

 inches long, issuing from each entrance chamber. There are from 

 three to five generations annually, depending on the locality and 

 season. 



The Oregon pine engraver (Ips oregoni (Eichh.) ) is distributed 

 throughout the interior forests of the Western States, where it 

 may be found breeding in almost any species of pine. It is most 

 commonly found attacking and killing interior ponderosa, Jeffrey, 

 and lodgepole pines (fig. 68). Large numbers develop in such host 

 material as windfalls, freshly cut logs, pieces of slash over 2 

 inches in diameter, and in the tops and limbs of trees killed by 

 Dendroctonus beetles. When conditions are favorable and suitable 

 host material is plentiful, they frequently develop in such numbers 

 as to become aggressive in their attacks on healthy living trees. 

 However, such outbreaks are usually of short duration and seldom 

 last more than one season. The most frequent damage is in the 

 killing of young replacement trees from 2 to 8 inches in diameter 

 and the top-killing of older trees. 



The adults are reddish brown to nearly black, about 1 i - inch 

 long, and have four small teeth along the margins on each side of 

 the elytral declivity. A typical sample of their work 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 anywhere 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 gen- 

 erations of this species a year, depending on the locality and the 



