MALE-PRODUCTION IN HYDATINA 



131 



TABLE 2 



These two lines of Hydalina senta, derived from sisters, one line reared in spring 

 water, the other in dilute butyric acid, show that butyric acid reduces the propor- 

 tion of male-producers. It also increases the size of family 



generations occur in greater degree in the generations immediately 

 follo-wdng them, which were reared in spring water? The possi- 

 bility was tested in the following experiment. 



Experiment 3. The general plan of the experiment was to rear, in 

 spring water, females whose grandmothers had been kept in manure 

 solution, and whose mothers were reared (except for a few hours after 

 hatching) in spring water. The details of the method were as follows : 

 Six or eight daughters of one female were divided into two lots of three 

 or four each, one being put into spring water, the other into manure 

 solution. Eight to 24 hours later these lots were transferred to new 

 dishes, one in spring water as before, the other in manure solution. 

 The transfer was made in order that the first young to hatch in the 

 second dish of manure solution might be known to have hatched from 

 eggs that underwent their maturation and part of their previous de- 

 velopment in manure solution. These first young, if females, were 

 transferred to spring water, in which (if they proved to be female- 

 producers) they were kept the rest of their lives. Their entire families 

 were reared to maturity and recorded. The totals for each lot of 

 families simultaneously reared are shown in table 3. 



