422 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 12 



The following curves show in a graphic way how the winged second 

 generation greatly increases its area of infestation over the area infested 

 by the first generation. The curves represent the infestation of eight 

 fields by both generations and are platted with equal value. 



1*5 »^ ft 

 UafjVj,S^JUJ JO b£v4.US0J9c£ 



Fig. 22. Curves based on Table II. 



