IV LETTEK OF SUBMITTAL. 



state, and national forests. The matter is presented in as brief and 

 concise a form as possible, in order that the information may be 

 readily available to the general reader, as well as to the forester and 

 student, and references are made to publications in which more 

 detailed accounts may be found. The statements and conclusions 

 relating to the insects and their work and to methods for their con- 

 trol are based almost entirely on investigations and observations by 

 Doctor Hopkins and by assistants in the Bureau of Entomology 

 working under his direction, carried on in all of the ])rincipal forest 

 areas of the United States. 



Respectfully, L. O. Howard, 



Entomologist and Chief of Bureau. 

 Hon. W. M. Hays, 



Acting Secretary of Agriculture. 



