22 



David Day Whitney 



duced earlier in a set of eggs than are the majority of the female- 

 laying females. In this generation the i8 mothers produced 

 only an average of i8 + eggs each, because the experiment was 

 discontinued at this point. 



TABLE XXI 



Continuation of the strain of which the beginning is recorded in the 12 generations of Table I. 



How a seemingly pure female-laying female strain is obtained 

 when only a few individuals are isolated from each generation 

 while a parallel strain does not yield the same results is not yet 

 clear. It may be due to some trick of selection in isolating the 

 young females of each generation. 



