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 
Bibliography 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 
