ILLUSTRATIONS. 



Plates. 



Page. 



Pirate I,— The spruces of Maine 50 



II. — Doidroctonus picecvperda Hopk. . u. sp . - _ _ . 52 



III. — Galleries and mines of the spruce- destroying beetles 54 



IV. — Galleries and mines of Dendroctowns picenperda in spruce. 5fi 



V. — Old galleries of Dendroctovus piceaperdft in spruce. , ...... 58 



VI. — Spruce barl^ showing growth of fungus, Polyporns vohrtfus .... 60 

 VII. — Cocoons of Bracon simplex, a parasite of the spruce-destroying 



beetle . 62 



VIII. — Work of secondary and other enemies of spriace . . 64 



IX. — Galleries of Polygrapliun rufipeniii^:, showing different stages 66 



X. — Mines of Tetrojnum cinnamopterum 68 



XI. — Work of Xyloteras hivittatii.s . _ _ . 70 



XII. — Work of Dendrocto7rns froiitalift and Dendroctnniis terebrans 72 



XIII. — Top of Black Spruce infested with a caterpillar and a plant-louse. 74 



XIV. — Dead spruce: also fir and birch ... . . . 76 



XV. — Timber flooded and killed by water on the Magalloway . 78 



XVI. — Sections of wood cut from Balsam Fir showing rapid growth aftet 



the old spruces die or are felled 80 



Text Figures. 



Fifi. 1. — Diagram illustrating the dormant and active periods of develop- 

 ment of Dendroctonns piceaperda. . 19 



2. — Trees girdled by different methods 32 



