LETTER OF TRANSMITTAL 



U. S. Department of Agriculture, 



Bureau of Entomology, 

 Washington^ D. 6'., August H^ 1912. 

 Sir: I have the honor to transmit herewith for publication as Tech- 

 nical Series No. 27, Part I, of this bureau a manuscript dealing with 

 the insects of the family Aleyrodida?, or white flies. This family in- 

 cludes several species of insects of the greatest economic importance, 

 and other species are attracting attention by reason of their increas- 

 ing abundance and injuries. The bureau is therefore frequently 

 called upon to determine these insects, not only from this country 

 but from many parts of the world. This family has been much 

 neglected by entomologists and there has thus not been established a 

 system of classification for the various forms. It is the aim of the 

 present paper to furnish this needed system of classification, which, 

 it is believed, will be found most useful to those interested in the 

 family. Part II will co^ain an account of the species of the large 

 and important genus Aleyrodes and will complete the monograph of 

 the family. 



Respectfully, L. O. Howard, 



Entomologist and Chief of Bureau. 

 Hon. James Wilson, 



Secretary of Agriculture. * 



m 



