113, U. S. P T 
ORGANIZATION OF THE UNITED STATES DEPARTMENT OF 
AGRICULTURE. 
Secretary of Agriculture Henry C. Wallace. 
Assistant Secretary C. W. Pugsley. 
Director of Scientific Work E. D. Ball. 
Director of Regulatory Work 
Weather Bureau Charles F. Marvin, Chief. 
Bureau of Agricultural Economics Henry C. Taylor, Chief. 
Bureau of Animal Industry John R. Mohler, Chief. 
Bureau of Plant Industry William A. Taylor, Chief. 
Forest Service W. B. Greeley, Chief. 
. ' , . ; f Walter G. Campbell, 
Bureau of Chemistry { *..*„..■. 
\ Acting Chief. 
Bureau of Soils Milton Whitney, Chief. 
Bureau of Entomology L. O. Howard, Chief. 
Bureau of Biological Surrey E. W. Nelson, Chief. 
Bureau of Public Roads Thomas H. MacDonald, Chief. 
Fixed Nitrogen Research Laboratory F. G. Cottrell, Director. 
Division of Accounts and Disbursements A. Zappone, Chief. 
Division of Publications John L. Cobbs,- Jr., Chief. 
Library Claribel R. Barnett, Librarian. 
States Relations Service A. C. True, Director. 
Federal Horticultural Board C. L. Marlatt, Chairman. 
Insecticide and Fungicide Board J. K. Haywood, Chairman. 
Packers and Stockyards Administration 1 Chester Morrill, 
Grain Future Trading Act Administration j Assistant to the Secretary. 
Office of the Solicitor R. W. Williams, Solicitor. 
This bulletin is a contribution from 
Bureau of Plant Industry William A. Taylor, Chief. 
Dry-land Agriculture Investigations E. C Chilcott, 
Agriculturist in Charge. 
28 ' 
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