INFLUENCE OF FOOD IN CONTROLLING SEX 



551 



the Dimaliella causes the percentage of male-producing daughters 

 to change from ahiiost zero to 63 + . 



The average size of a family of daughters from each mother 

 was 16 + . The size of the families in tables 1 and 2 were inten- 

 tionally made small because of the labor entailed had they been 

 made larger. In table 3 the mothers seemed unable to bear 

 the strain of being transferred from the Polytoma diet to the 

 Dunaliella diet for the second time and usually soon died. It 

 is possible that some of them were producers of small famihes, 

 as Shull has shown in some of his experiments. 



TABLE 2 



Showing that young adult female-producing females reared on a Polytoma diet will 

 continue to produce female-producing daughters but can be forced to produce a 

 high percentage of male-producing daughters by being put upon a Dunaliella diet 

 and later can be forced to produce again female-producing daughters by being put 

 back upon the Polytoma diet 



