J. M. WOODLOCK 185 



The preponderance; of males is probably <lue to the fact that 28 out 

 of the 30 went straight through in the autumn without hibernating, 

 only 7 of those that hibernated finally emerging in March 1915. 



D (i). July 27th, IIIU, [irossulnriata ^ (from family li) x" Q" J. 

 This gave : 



4: grossulariata (f , 2 grussuUtriata ^, 3 " Q" ^, 3 "Q" %,Mai:ti- 

 color $ . 



(ii) October 30th, 1914, grossulariata t^ (from A (ii))x"Q" % 

 gave only 1 grossulwriata ,} , 1 " Q " ? , 2 (acticolor $ . 



E. November 10th, 1914, grossulariata ^ (from family J) (i)) 

 X grossulariata ? (from family B) gave only 2 " Q " %. 



At this stage the results were submitted to Dr Doncaster, who 

 suggested that they might be explained in the same way as the 

 production of a coloured flower by crossing two different whites in the 

 sweet-pea, or perhaps arc more nearly comparable with the production 

 of a wild-coloured rat or rabbit by crossing an albino with a black. 



It is clear that the typical grossulariata pattern must depend on 

 the presence of two factors, which may be called G and T. In the 

 absence of the factor G the moth is lacticolor, and this factor is 

 sex-limited in inheritance, normal males being GG, females Gg. 



The factor T is necessary for the production of the type form : 

 when it is absent (or if a notation be preferred which does not commit 

 one to the presence-and-absence hypothesis, when it is modified to 

 Q) the moth is of the variety " Q." A normal grossulariata male is 

 thus GGTT, female GgTT ; a "Q" male GGtt (or if preferred it may 

 be written GGQQ), "Q" female Ggtt ; a lacticolor male and female 

 ggTT. 



If now a " Q " male is mated with a lacticolor female, the result will 

 be the production of typical grossulariata if the lacticolor is carrying 

 the factor T, thus 



" q" ^ = GGtt X ggTT = lacticolor % 



/ 

 rf" GgTt GgTt ? , 



and when the F^ moths are mated together the result will be, in the 

 males, typical grossulariata. and " Q " in the ratio of 3 : 1, and in the 

 females grossulariata, lacticolor, and " Q " in the ratio of 3 : 4 : 1, thus : 



