INDEX. 



Page. 



Adult, character 11 



Attack, influences aiding or inducing 16 



Birds as natural enemies 18 



Cold, as affecting infestation 16 



Colorado Dendroctonus, distinguishing characters .11 



Control, in Black Hills _ 19-20 



in Colorado 20 



methods 19, 21 



Damage, extent 5 



Dendroctonus approximatus, distinguishing characters 11 



Colorado. See Dendroctonus approximatus. 

 Douglas spruce. See Dendroctonus pseudotsugse. 



monticola, distinguishing characters 11 



piceaperda, distinguishing characters 11 



work in dead Engelmann spruce 10 



ponderoscB — subject of this bulletin. 



pseudotsugse, distinguishing characters 11 



in western larch 11 



work in dead Douglas spruce 10 



rufipennis, wrong determination 6 



terebrans, wrong determination 6 



vaJens, attacking fire-scorched trees 17 



distinguishing characters 11 



Destructiveness 5 



Development, time required 16 



Diseases 18 



Distribution 5 



Douglas spruce, attacked by Dendroctonus pseudotsugse 10 



Dendroctonus. See Dendroctonus pseudotsugse. 



Drought, as affecting infestation 16 



Eggs, time of depositing 15 



Enemies, insect 18 



Fire, as affecting infestation 16 



Food plants 5 



Fungous diseases 18 



Gallery, character 11 



Infested trees, indications of attack 13 



Larch, western, attack of Dendroctonus pseudotsugse 11 



Larvae, diseases 18 



habits 15 



Life history 15 



23 



