40 THE METHODS AND 



represent all the factors involved, and show 

 how each behaves in descent. Such a system 

 or scheme we have at length discovered, and 

 I incline to think that it must be the true 

 one. If you study this case you will find that 

 there are nine distinct kinds of matings that 

 can be made between the variety, the type 

 and the hybrid, and the scheme fits the whole 

 group of results. It is based on two suppo- 

 sitions : 



1. That the female is cross-bred, or as 

 we call it heterozygous for femaleness-factor, 

 the male being without that factor. The eggs 

 are thus each destined fi'om the first to be- 

 come either males or females, but as regards 

 sex the spermatozoa are alike in being non- 

 female. 



2. That there is a repulsion between the 

 femaleness-factor and the grossnlariata factor. 



Such a repulsion between two factors we 

 are Justified in regarding as possible because 



-^mm^mmmmm 



