332 
A. D. Darbishire. 
The second cross:— 
alba 2 X dioica g giving rise to females 2 $ and males g £ • 
Bateson has suggested a simpler theory which does not involve 
the assumption of a special factor for the monoecious character, and 
in which the female is heterozygous. It is as follows:— 
dioica 5 has egg-cells 5 and g . 
dioica g has pollen all g . 
alba $ has egg-cells 2 and g ; and pollen all 5 . 
The above matings would then give the following results:— 
dioica 2 X dioica g gives females 2 g and males g <?. 
dioica ? X alba g gives pure females 2 2 and heterozygous 
females 5 g . 
alba 2 x dioica g gives females 2 g and males g g . 
The reader is referred to Professor Bateson’s Mendel's 
Principles of Heredity, p. 168, for a detailed justification of the 
assumptions involved in his hypothesis. 
Let us now proceed to a consideration of the remarkable case 
of Abraxas grossulariata —the common yellow, black and white 
moth that infests our currant and gooseberry bushes—which has 
been worked out by Raynor and Doncaster. There is a variety of 
this moth the character of which is fairly well conveyed by the 
name which has been given to it—var. lacticolor : it differs from the 
normal type in the great reduction in the size of the black spots. 
The type and its varieties are figured on Plate I. (facing p. 44) of 
Professor Bateson’s Mendel's Principles. This lacticolor variety is 
known exclusively as a female. 
The following crosses between it and the normal species were 
made, and gave the results indicated :— 
1. lact. 2 x gross, g gave s and 5 s, all gross. 
2 . F x gross. ? x F x gross, g gave gross, g s and ? s, and 2 
lact. ; no male lact. being formed. 
3. lact. 2 X F x gross. g gave all four possible types, viz., gross, 
g s and J s; and lact. g s and ?s; the lacticolor males being the 
first ever seen. 
4. Fj gross. 2 X lact. g gave all g sgross.andall J s lacticolor. 
The theory by means of which Doncaster sought to account 
for these remarkable phenomena was based on Castle’s theory of 
sex, according to which each sex is a heterozygote in respect of sex. 
It embraced the following hypotheses :— 
1. Each sex gives off g - and ?-bearing gametes. 
2. In 2 s which are heterozygous in respect of colour, gametic 
