342 



ECONOMIC ENTOMOLOGY 



by Hopkins and Swaine.) Reference can be made here to only a few 

 of the economic wood-boring beetles that do an immense amount of 

 injury to the forests of the United States and Canada: 



1. Dendrocloniis horealis Hopk., Attacks spruce of the western forests in Alberta 

 and British Columbia. 



2. D. brevicomis Lee, Western yellow pine. 



3. D. engelmanni Hopk., Engelmann's spruce of the west. 



4. D. monticolw Hopk., Western pines (Figs. 226 and 227). 



5. D. fmirrayancB Hopk., The lodge-pole pine of the West; not injurious. 



6. D. obesus Lee, The Sitka spruce. 



Fig. 226. — The wes- 

 tern pine borer {Dendroc- 

 tonus monticoloe. {After 

 Swaine, Bui. 14, Ent. Bur. 

 Can.) 



Fig. 227. — Larva of Dendroctomis monlicolce. 

 {After Swaine, Bid. 14, Enl. Bur. Can.) 



7. D. piccapcrda Hopk., Eastern spruces. 



8. D. pseudolsiigce Hopk., The Douglas fir and western larch. 



9. D. simplex 'Lee, Larch (Eastern). 



10. D. valcns Lee, Pinus and Picea. 



11. Dryoccetcs confusus Sw., Alpine fir of British Columbia and Alberta. 



12. Polygraphus rujipennis Ky., Spruces throughout Canada. 



13. Pityoklcines sparsusLec, Balsam fir in the east. 



The bark-beetles are small (1-9 mm. long), brownish or black, and 

 usually cylindrical beetles. One group, the Ambrosia bark-beetles 

 make their tunnels in the wood whose walls are stained black by the 

 growth of the fungus Ambrosia which nourish them. The other 

 group — the true bark-beetles— make their tunnels in the bark or 

 between the bark and the wood. 



