IV LETTER OF TRANSMITTAL. 



important groups represented by species which depredate on trees 

 and forest growths. The present paper includes the partial results of 

 his preliminary work, which has been prosecuted with such energy as 

 to leave little more to be done in this line. Mr. Rohwer's future papers 

 will deal with special groups which will be treated in a monographic 

 manner in order that a basis may be formed for special papers on the 

 economic features, 



I recommend the publication of this manuscript as Technical 

 Series No. 20, Part II, of the Bureau of Entomology. 

 Respectfully, 



L. O. Howard, 



Chief of Bureau. 



Hon. James Wilson, 



Secretary of Agriculture. 



