LETTER OE TRANSMITTAL 



U. S. Department of Agriculture, 



Bureau of Entomology, 

 W(t)<hhigt<>)i^ D. 6'., F'ehruat'u 5, 1907. 

 8ir: I have the honor to transmit herewith the manuscript of a 

 paper by Mr. Dudle}^ Moulton, special agent in this Bureau, entitled 

 "'A Contribution to our Knowledge of the Thysanoptera of California/' 

 'Phis paper embodies the results of some work carried on l)y Mr. Moulton- 

 while a student at the Leland Stanford ffunior University, Palo Alto, 

 Cal., and forms part of a thesis for the degree of Master of Arts in 

 the Department of Entomology at that institution. It contains ke3^s 

 and descriptions for the identification of the various species of thrips 

 found to occur in California. The group of insects treated is one of 

 economic importance, containing, as it does, species which are injuri- 

 ous to various field crops, fruit trees, and ornamental plants. I recom- 

 mend tlie publication of the paper as Technical Series. No. 12, Part III, 

 of this Bureau. 

 , Respectfully, L. O, Howard, 



Entomologist and Chief of Bureau. 

 Hon. James Wilson, 



Secretary of Agriculture. 



