DEGENERATE SEXUAL REPRODUCTION. 173 



genesis was not for any subsequent advantage, but purely from 

 necessary internal conditions. 



X The Case of Bees.— We have already spoken of the " voluntary 

 parthenogenesis" of bees. All the eggs are supposed to have the power of 

 parthenogenesis, but all are not allowed so to develop. The fertilized eggs 

 develop into queens and workers, the unfertilized give rise to drones. Weis- 

 mann emphasizes the fact that the ova are all alike. "There is no difference 

 between those which are, and are not to be fertilized. The difference first 

 appears after the maturation of the egg, and the removal of the ovogenetic 

 plasma." The state of the polar bodies is not known, so the question need not 

 be complicated by suppositions about them.* Writing before his discovery in 

 regard to parthenogenesis, he says the sine qua non of development is that the 

 nucleus acquire a certain quantity of germ-plasma ; the fertilized egg gets its 

 quantum in the usual way by aid of the sperm, the unfertilized gets it by simple 

 growth ; the difference of sex in the result need not be further taken into 

 account. Agai.i we remark that this matter of a quantum of " germ-plasma," 

 and the two ways of getting it. is a pure supposition, both in general and in this 

 particular case. Again we must note, that if parthenogenesis be decided on 

 utilitarian principles, and if the difference of sex need not be taken into account, 

 and if the eggs are all the same to start with, we see some difficulty in under- 

 standing the persistence of drones and sexual reproduction at all. It is a 

 laborious and expensive way of attaining no obvious gain. But we should, 

 indeed, like to be sure that the ova are all the same to start with. Von Siebold 

 said that the queen was moved by the sight of the different size of the cells to 

 fertilize or refrain from fertilizing. This may be so. Impressive as a queen's 

 cell is, the difference between a worker's and drone's is much less striking. 

 We suspect the impulse lies somewhere else. But barring this, the eggs laid 

 first, when the queen is at its prime, develop into females ; the eggs which give 

 rise to drones come later, when the mother is more exhausted. They have had 

 less chance of differentiation — they are parthenogenetic ova. So with old 

 queens, when the stock of sperms is also of course exhausted. Weismann 

 quotes the experiment which Bessels made, after Dzierzon. - The nuptial flight 

 was prevented, and ova which, in the course of nature, would have been 

 fertilized and given rise to queens and workers, were of course unfertilized, and 

 developed parthenogenetically into males. This proves, he says, that the ova 

 are all the same to start with. But one would like to know whether the 

 prevention of the nuptial flight had not also its effect upon the ova, and whether 

 the parthenogenetic ova are not always less differentiated. 



*See, however, p. 168, note. 



