LETlliR OF TRANSMITTAL 



U. S. Department of Agriculture, 



Bureau of Entomology, 

 Washington, D. 61, September 10^ 1906. 

 Sir: I have the honor to submit herewith a manuscript entitled 

 "A Revision of the Tyrogl^^phidtv of the United States," prepared b}'^ 

 Mr. Natlian Banks, assistant entomologist. Mites belonging to the 

 family Tyroglyphidtig are destructive to a variety of stored products 

 and other conmiodities, certain species injure living plants, while 

 others are useful because they destroy certain injurious insects. The 

 group is therefore one of very considerable economic importance. 

 This paper b}' Mr. Banks should prove a valuable contribution to the 

 stud}' of these mites and greatly facilitate the determination of the 

 different species; I therefore recommend it for publication as Technical 

 Series, No. 13, of this Bureau. 

 Respectfully, 



F. H. Chittenden, 



Acting Chief of Bureau. 

 Hon. James Wilson, 



tSecretary <f Agrlctdture. 



