42 THE EVOLUTION OF SEX. 



In the first brood, by feeding one set with beef, Yung raised the 

 percentage of females from 54 to 78; in the second, with fish, 

 the percentage rose from 6 1 to 8 1 ; while in the third set, when 

 the especially nutritious flesh of frogs was supplied, the per- 

 centage rose from 56 to 92. That is to say, in the last case the 

 result of high feeding was that there were 92 females to 8 males. 

 From the experience and carefulness of the observer, these 

 striking results are entitled to great weight. 



{b) Case of Bees. — The three kinds of inmates in a beehive 

 are known to every one as queens, workers, and drones ; or, as 

 fertile females, imperfect females, and males. What are the 

 factors determining the differences between these three forms ? 

 In the first place, it is believed that the eggs which give rise to 

 drones are not fertilised, while those that develop into queens 

 and workers have the normal history. But what fate rules the 

 destiny of the two latter, determining whether a given ovum 



The Queen (a), Worker (c), and Drone (b) 

 of the Coinmi-in Hive-Bee. 



will turn out the possible mother of a new generation, or remain 

 at the lower level of a non-fertile working female ? It seems 

 certain that the fate mainly lies in the quantity and quality of 

 the food. Royal diet, and plenty of it, develops the reproductive 

 organs of the future queens ; sparser and plainer food retards 

 the sexuality of the future workers, in which reproductive organs 

 do not develop. Up to a certain point, the nurse bees can 



