No. 589] SHORTER ARTICLES AND DISCUSSION 



51 



of male-producing females produced was about 18 per cent. It 

 also caused an increase in the number and the rate of production 

 of the eggs by each female as was the case in the FeCl 3 experi- 

 ments. KC1 (itf/12,000) in the very few experiments recorded 

 caused about 16 per cent, of male-producing females to appear 

 and CaCl 2 (if/12,000) caused about 33 per cent, of male-produ- 

 cing females to appear. In the controls for these experiments no 

 male-producing females appeared. In all of these chemical ex- 

 periments each mother after being transferred from the control 

 to the culture media containing the various chemicals produced a 

 family of several daughters but in each family there was never 

 more than one male-producing daughter. In the FeCl 3 solutions 

 each mother produced many daughters and as only one of them 

 in each family was a male-producer the percentage of male-pro- 

 ducing females was necessarily lower whereas in the HgCL. KC'l. 

 CaCl 2 , solutions each mother produced fewer daughters than in 

 the FeCl 3 solutions, and as only one of these in each family was 

 a male-producer, the percentage of male-producing females was 

 consequently higher. Various dilutions were used of A1C1 3 , 

 KCN, NaCl, Na 2 HAs0 4 , HC1, and NaOH but none of them caused 

 male-producing females to appear. 



In the nutrition experiments it was found that a constant diet 

 at a uniform temperature of 15° C.-17 C. or 25° C.-27 C. pro- 

 duced only female-producing females but in some experiments 

 in which an abundance of food was used for a time and then was 

 followed by a period of scanty food or semi-starvation many 

 male-producing females appeared, especially at the lower 

 temperature. 



In some of the experiments a temperature of 15° C -17° C. pro- 

 duced all female-producing females but when the mothers were 

 put at a temperature of 25° C.^27° C. or at 31° C. as high as 50 

 per cent, of the daughters were male-producers. When these 

 same mothers were transferred back to 15° C.-17° C. they again 

 produced only female-producing daughters. In a few experi- 

 ments at a constant temperature of 25° C.-27 C. only female- 

 producing females were produced but when the mothers were put 

 at a lower temperature they produced many male-producing 

 daughters. The general conclusion drawn is that whenever the 

 general cultural conditions are constant and uniform, whether 

 they refer to nutrition or to temperature, only female-producing 

 females are produced but when the cultural conditions are sud- 



