LETTER OF TRANSMITTAI. 



U. S. DEPARTMENT OF AGRICULTURE, 



BUREAU OF CHEMISTRY, 

 Washington* />. <'.. F<l>rnjW,190%. 



SIR: I have the honor to transmit for your inspection and approval 

 the manuscript of a bulletin prepared in this Bureau by Mr. J. K. 

 Haywood, cooperating with the Division of Entomology. I recom- 

 mend that this manuscript be published as Bulletin No. 68 of the 

 Bureau of Chemistry. 



Respectfully, H. W. WILEY, 



Chief of Bureau. 

 Hon. JAMES WILSON, 



Secretary of Agriculture. 



