378 



Experimental Zoology 



The results seem to show a sHghtly larger number of females 

 in the well-fed lots, and a larger number of males in the starved 

 sets; but the numbers are too small to justify any conclusions 

 from them, and those that die may have altered the proportions. 

 In other experiments the authors found that the results do not 

 lead to any conclusions in regard to the influence of nourishment. 



The possible influence of food in determining the sex of the egg 

 (or sperm) was also examined. In the following table those larvae 

 that had the optimum amount of food are indicated by o. Those 

 that had a minimum of food are indicated by M. The amount 

 of food given to the grandparents, to the parents (third column), 

 and to the larvae themselves (second column) is indicated by the 

 letters. 



It is not evident from these data that the sex of the egg is 

 influenced by the condition of the parents or grandparents. 



Cuenot has carried out in recent years some important experi- 

 ments with moths and flies. When the caterpillars of Ocneria 

 dispar were given an abundant nourishment, they produced 52 

 females and 4 males. Caterpillars of Bombyx rubi were given 

 so small an amount of food that great mortaHty resulted. Of 

 the 27 survivors there were 13 males and 14 females. 



Cuenot states that in the maggots of flies, the gonads, although 

 present in young larvae, do not undergo their histological differ- 

 entiation until a relatively late period of larval life, hence 

 there might appear a better opportunity to influence the sex, 



