

Vol. XX FEBRUARY 15, 1921 No. 10 



JOURNAL OP 



AGRICULTURAL 

 RESEARCH 



CONTENTS 



Page 



A Transmissible Mosaic Disease of Lettuce - - - 737 



IVAN C. JAGGER 

 (Contribution from Bureau ot Plant Industry) 



Leconte's Sawfly, an Enemy of Young Pines - 741 



WILLIAM MIDDLETON 



(Contribution from Bureau of Entomology) 



Amylase of Rhizopus tritici, with a Consideration of Its 



Secretion and Action ------- 7oi 



L. L. HARTER 



( Contribution from Bureau of Plant Industry) 



A Comparative Study of the Composition of the Sunflower 



and Corn Plants at Different Stages of Growth - - 787 

 R. H. SHAW and P. A. WRIGHT 



(Contribution from Bureau of Animal Industry) 



PUBLISHED BY AUTHORITY OF THE SECRETARY OF AGRICULTURE, 



WITH THE COOPERATION OF THE ASSOCIATION OF 



LAND-GRANT COLLEGES 



WASHINGTON, D. C. 



WA8HINQTON : GOVERNMENT PRINTING OFFICE : I0St 



