40 THE METHODS AND 



pale variety called lacticolor. With these 

 two forms Doncaster has made a remarkable 

 series of experiments. When he began, lacti- 

 color was only known as a female form. This 

 was crossed with the grossulariata male and 

 gave grossulariata only, showing that the 

 male was pure to type. The hybrids bred 

 together gave grossulariata males and females 

 and lacticolor females only. But the hybrid 

 males bred to lacticolor females produced 

 all four combinations, grossulariata males 

 and females, and lacticolor males and females. 

 When the lacticolor males were bred to gros- 

 sulariata females, whether hybrid, or wild 

 from a district where lacticolor does not 

 exist, the result was that all the males were 

 grossulariata and all the females lacticolor I 

 It is difficult to follow the course of such an 

 experiment on once hearing and all I ask 

 you to remember is first that there is a series 



