24 INDEX. 



Page. 



Lightning, as cause of infestation 16 



Mountain-pine beetle. See Dendroctonus monticola. 



Natural enemies 18 



Neutral insects 18 



Oregon Tomicus. See Tomicus oregoni. 



Parasitic enemies 18 



Picea canadensis, attack of Dendroctonus ponderosse 5 



engelmanni, attack of Dendroctonus ponderosse 5 



Pine, bull. See Pinus ponderosa. 

 limber. See Pinus Jlexilis. 

 western yellow. See Pinus ponderosa. 



Pinus Jlexilis, attack of Dendroctonus ponderosse 5 



ponderosa, attack of Dendroctonus ponderosse 5 



Pitch tubes - 13 



Predaceous enemies - 18 



Remedial measures. See Control. ' 



Secondary enemies of trees 18 



Spruce, Douglas, attack of Dendroctonus pseudotsugse 10 



Engelmann. See Picea engelmanni. 



attack of Dendroctonus piceaperda 10 



See also Picea engelmanni. . . 



white. See Picea canadensis. 

 Spruce-destroying beetle. See Dendroctonus piceaperda? 



Storm-felled trees, inducing infestation 16 



Temperature, as affecting infestation 16 



Tomicus oregoni, attack on trap trees 18 



Oregon. See Tomicus oregoni. 



Trap trees 7, 17 



Turpentine beetle, large red. See Dendroctonus valens. 



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