EGG PRODUCTION BY ADULT MALE-PRODUCING FEMALES. 319 



Many observations were made in the pairing of different young 

 females with males. All young females observed were seen to 

 be injected with active sperm from the male. Each female was 

 then placed in a separate watch-glass and allowed to mature and 

 to produce eggs or viviparous young. Some of these young 

 females which were seen to receive living sperm into their body 

 cavities developed parthenogenetic young daughter females ana 

 others developed fertilized thick-shelled resting eggs. It has been 

 shown by Maupas, 1 Lauterbaum, 2 Whitney, 3 and Shull 4 that if the 

 young male-producing female pairs with a male thick-shelled 

 fertilized eggs will be produced, but it has never been demon- 

 strated that in pairing the female-producing females also receive 

 sperm into their body cavities in the same manner as do the male- 

 producing females. 



Larger and more mature parthenogenetic female-producing 

 females as well as larger and more mature male-producing females 

 were placed with males and many observations made. The male 

 and female individuals come into contact with each other and 

 the male assumes the same position as with the young females. 

 The male makes several attempts to pierce the cuticle of the 

 female with the piercing copulatory organ but is unsuccessful 

 and in some instances sheds the sperm out into the water on the 

 outside of the body of the female. These sperm are active for 

 a few seconds, but soon become inactive and, owing probably 

 to the injurious effects of the water, soon die. This failure 

 of the male to inject sperm into the body cavity of both the adult 

 female-producing female and the adult male-producing female 

 was observed many times and in every case it was a failure. In 

 some instances, the sperm were not shed into the water by the 

 male. This seemed to depend more or less upon the condition 

 of the male. If it had been isolated alone for several hours and 

 was young it would shed the sperm out into the water when in 

 contact with the female but if it was old and partly spent it 

 would not shed the sperm out into the water. 



1 Maupas, M., C. R. Acad. Sci. Paris, T. CXI., 1890. 

 2 Lauterborn, Biol. Centralb., XVIII. , 1898. 

 3 Whitney, D. D., Jour. Exper. Zool., V., 1907. 

 * Shull, A. F., Jonrn. Exper. Zool., VIII., 1910. 



