490 



AUSTIN RALPH MIDDLETON 



though in four days of the first period the reverse is true. In 

 all the other twenty-six days the average of the fast lines was 

 above that of the slow. The table shows a gradual increase in 

 the number of generations produced by the fast lines relative 

 to those produced by the slow, the excess in favor of the fast 



«0 I— 



Fig. 14-a Polygon of the average number of generations per line per three 

 day period produced by the fast and slow sets of lines of Experiment 3-A (direct 

 selection in opposite directions of the progeny of the second wild individual). 

 The continuous line is the curve of the fast set, the broken line, the curve of the 

 slow set. The ordinates are the averages, the abscissae the three-day periods. 



Fig. 14-b Curve of the difference (in favor of the fast lines) between the 

 average number of generations per line per three-day period produced by the 

 fast and slow sets of lines of Experiment 3-A (direct selection). The ordinates 

 are the differences between the averages; the abscissae, the consecutive three- 

 day periods. Note the progressive increase of the difference under opposite 

 selection. 



