XII THE SCOLYTID BEETLES. 



Detailed information on the species — Continued. 



No. 22. The black turpentine beetle — Continued. Fage. 



Economic features 150 



Evidences of attack 150 



Favorable and unfavorable conditions for the beetle 151 



Methods of control 151 



Basis of information 153 



Bibliography 153 



No. 23. The red turpentine beetle (Dendroctonus valens Lee.) 153 



Seasonal history 155 



Overwintering stages 155 



Activity of overwintered broods 155 



Generation 156 



Habits 156 



Economic features 160 



Evidences of attack 161 



Effects on commercial value of the wood 161 



Favorable and unfavorable conditions for the beetle 161 



Methods of control • 162 



Basis of information 163 



Bibliography 165 



General bibliography (economic literature) 166 



