CROWDING AND SEX DETERMINATION 



307 



of M. macrocopa females as measured by the time before the pro- 

 duction of the first (parthenogenetic) brood. When tested under 

 crowded conditions, the retarding effect normally accompanying 



Fig. 30. — Diagram, from Banta and Brown 19296, showing the relation (.4) between 

 the amount of retardation of the production of young and the percentage of males pro- 

 duced in Moina macrocopa, and (5) between the number of mothers per bottle and the 

 percentage of males produced. 



