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CONTENTS. 



Page. 



Request, authorization, and instructions 7 



The investigating trip 7 



The conditions observed 7 



The amount of dead timber • 7 



Historical references 7 



The trouble caused by insects 9 



The primary enemy 9 



Name of the beetle 9 



Secondary enemies 10 



The Oregon Tomicus ( Tomicus oregoni Eichh. ) 10 



The coarse- writing bark-beetle ( Tomicus calligraphus Germ. ) 11 



The wood-engraving Tomicus (Tomicus cxlatus Eichh. var. scopulorum, 



n. var.) 12 



The dark-red turpentine beetle (Dendroctonus valens Lee. ) 12 



The western pine Hylurgops (Hylurgops subcostulatus Mann. )■■..... 13 



The pine-root bark-beetle (Hylastes porosus Er. ) 13 



Branch and twig beetles 14 



Ambrosia or timber beetles and wood-boring grubs 14 



Small trees dying from other causes 14 



The rock pine pitch-worm 14 



The pine weevil 14 



Insect enemies of the foliage 15 



Natural enemies of the destructive and injurious insects 15 



Predaceous enemies 15 



The bluish-green predaceous beetle 15 



Clerid beetles and their larvge 15 



Eed-bug enemy of the bark-beetle ( Trogosita virescens Fab. ) 16 



Other predaceous beetles 16 



Parasitic insects 16 



Parasitic fungi 16 



Birds as enemies of the destructive beetle 16 



How the trees are attacked and killed 17 



Characteristic features of the living, dying, and dead trees infested and killed 



by the beetle 19 



Borings and pitch tubes 19 



Appearance of the leaves. .' 19 



Appearance of the trees that have been dead three years or more 19 



Evidence of the work of the beetle on old dead trees 20 



The relation of wood-boring insects and wood-destroying fungi to the rapid 



deterioration of the wood 2C 



3 



