• ILLUSTRATIONS. 



Page. 

 Plate I. Fig. 1. — The pine-destroying beetle of the Black Hills. Fig. 2. — De- 

 structive pine bark-beetle. Fig. 3. — Spruce-destroying beetle 56 



II. Fig. 1. — Work of the Lawson's cypress bark-beetle in twigs of living 

 trees. Fig. 2. — The Lawson's cypress bark-beetle. Fig. 3. — The 



redwood bark-beetle (Phlceosinus sequoise Ffopk. ) 56 



III. Work of the pine-destroying beetle of the Black. Hills 56 



IV. Figs. 1 and 2. — Work of the Oregon Tomicus. Fig. 3. — Work of the 



yellow pine wood-engraver 56 



V. Work of the spruce-destroying beetle 56 



VI. Work of the destructive pine bark-beetle 56 



VII. Work of Dendroctonus frontalis and Dendroclonus terebrans 56 



VIII. Work of the pine-destroying beetle of the Black Hills 56 



IX. Work of the pine-destroying beetle of the Black Hills 56 



X. Work of the Oregon Tomicus 56 



XI. Work of the pine-destroying beetle of the Black Hills Forest Reserve. 56 

 XII. Fig. 1. — Cocoons of Br aeon simplex, a parasite of the spruce-destroying 

 beetle. Fig. 2. — Work of the pine-destroying beetle of the Black 



Hills 56 



XIII. Galleries and mines of the spruce-destroying beetle 56 



XI V. Galleries and mines of the spruce-destroying beetle in spruce 56 



XV. Old galleries of the spruce-destroying beetle 56 



XVI. Work of the yellow pine wood-engraver 56 



XVII. Work of timber and bark beetles in spruce 56 



XVIII. Work of secondary and other enemies of spruce 56 



XIX. Galleries of the spruce bark-beetle, showing different stages 56 



XX. Mines of the destructive spruce wood-borer 56 



XXI. Dead spruce; also fir and birch 56 



XXII. Work of the redwood bark-beetle 56 



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