38 THE METHODS AND 



absent from the male and following the 

 ordinary Mendelian rules. 



Before showing you how the Sweet Pea 

 phenomenon aids in this inquiry I must tell 

 you of some other experimental results. The 

 fii'st concerns the common currant moth, 

 Abraxas grossulariaia. It has a definite 

 pale variety called lacficolor. With these 

 two forms Doncaster has made a remarkable 

 series of experiments. When he began, lacti- 

 eolor 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 la^^ticolor males were bred to gros- 

 sulariata females, whether hybrid, or wild 



