Internal Factors of Sex Determination 409 



other kind resulting from the united nuclei. The former should 

 produce only male parts, because this is what happens when the 

 egg is not fertilized; the latter should produce female parts, 

 as does a fertilized egg. In other words, the results in the differ- 

 ent parts of the single, imperfectly fertilized egg are the same as 

 those formed in unfertilized and fertilized eggs. 



I have pointed out that the results are capable of being equally 

 well explained in another way. It has frequently been noted 

 that two spermatozoa occasionally enter the egg of the bee. If 

 we suppose one of these only conjugates with the female nucleus, 

 its products should produce female parts, while the other sperm 

 nucleus that fails to conjugate will, if it divides and produces 

 nuclei, give rise to male parts. Boveri's view and my own are 

 not mutually exclusive : either process may at times take place 

 and produce gynandromorphs. I have pointed out how it might 

 be possible under certain conditions to determine whether the one 

 or the other process has taken place. In a case like that de- 

 scribed by von Siebold, in which the mother belongs to one race 

 and the father to another, the parts of the embryo that contain 

 the single nucleus should be like the mother on Boveri's view, 

 and like the father on my own ; in both, the parts supplied by 

 the conjugated nuclei produce a hybrid result. An example 

 may make this clearer. Let us suppose, as in von Siebold 's 

 case, that the queen is Italian and~ the male a German drone. 

 If one spermatozoon enters the egg and conjugates with one 

 of the first two segmentation nuclei, as on Boveri's view, the 

 male parts of the embryo that come from the single segmentation 

 nucleus must be like the mother, i.e. they should have the char- 

 acter of the Italian bees ; the parts that come from the conjugat- 

 ing nuclei should be hybrid. On my view two spermatozoa enter 

 the egg, one only conjugating with the egg nucleus. The male 

 parts will come from the single sperm nucleus, and will, there- 

 fore, be like the father, i.e. they will have the character of the 

 German bees; the parts that come from the conjugating nuclei 

 will be hybrid in character. Thus on my view the male parts of 

 the gynandromorphous hybrid will be paternal; on Boveri's 



