32O D. D. WHITNEY. 



This ability of the male to pierce through the cuticle of young 

 females and the failure to pierce through the cuticle of adult 

 females is due, probably, to the increased thickness or compact- 

 ness, or both, of the cuticle of the older females. As the females 

 grow and become older their cuticle, which is supposedly of more 

 or less chitinous material, becomes more difficult to penetrate. 

 It is highly probable that if the sperm could be injected into the 

 body cavity of the adult male-producing females that the eggs 

 would be fertilized and thick-shelled resting eggs would be 

 produced. 



Males do not seem to be able to discriminate either between 

 each other or young females of either kind or mature females. 

 They attempt to pair with any other individual with which 

 they come into contact. Males have been seen to inject sperm 

 into the body cavities of each other. Many males from a 

 general mixed culture often contain a few free sperm actively 

 swimming around in their body cavities. These sperm have been 

 placed in their body cavities by other males. Thus it happens 

 that more or less of the sperm of a male may be wasted by being 

 injected into either young female-producing females or into 

 other males, or even shed out into the water in attempted 

 impossible copulation with adult females. 



SUMMARY. 



1. Both kinds of young females, female-producing and male- 

 producing, pair with male individuals and receive active sperm 

 into their body cavities. 



2. The young female-producmg females having been injected 

 with living sperm by the male mature and produce partheno- 

 genetic daughter-females but the young male-producing females 

 having been injected with living sperm by the male mature and 

 produce thick-shelled fertilized eggs. 



3. Male individuals pair and inject active sperm into the body 

 cavities of each other. 



4. The mature female-producing females and the mature 

 male-producing females pair with male individuals but do not 

 receive sperm into their body cavities because the copulatory 



