CONTENTS. IX 



Page. 

 Detailed information on the species — Continued. 



No. 4. The southern pine beetle (Dendroctonus frontalis Zimm.) 56 



Seasonal history 57 



Northern section 57 



Overwintering stages 57 



Activity of overwintered broods 57 



First generation 58 



Second generation 59 



Third generation 59 



Fourth generation , . . 59 



Fifth generation 60 



Periods of destructive attack 60 



Southern section 60 



Habits 60 



Economic features 63 



Evidences of attack 64 



Effects on commercial value of the wood 65 



Favorable and unfavorable conditions for the beetle 65 



Methods of control 67 



Basis of information 70 



B i bl iography 72 



No. 5. The Arizona pine beetle (Dendroctonus arizonicus Hopk.) 72 



Seasonal history 72 



Basis of information 73 



Bibliography 73 



No. 6. The smaller Mexican pine beetle (Dendroctonus mexicanus Hopk.). . 74 



Bibliography 75 



No. 7. The larger Mexican pine beetle (Dendroctonus parallelocollis Chap.). 75 



Bibliography 75 



No. 8. The Colorado pine beetle (Dendroctonus approximates Dietz) 76 



Seasonal history 77 



Overwintering stages 77 



Activity of overwintered broods 77 



Generation 77 



Habits 78 



Economic features 78 



Basis of information ". . 79 



Bibliography 80 



No. 9. The mountain pine beetle (Dendroctonus monticolse Hopk.) 80 



Seasonal history 81 



Overwintering stages 81 



Activity of overwintered broods 81 



Generation 82 



Habits 83 



Economic features 84 



Evidences of attack 84 



Effects on commercial value of the wood 85 



Favorable and unfavorable conditions for the beetle 86 



Methods of control 87 



Basis of information 89 



Bibliography 90 



