138 The Inheritance oj Wing-Colour in Lepidoptera 



Conclusions. 



1. In Abraxas grossulariata the factor for the black pattern of 

 var. varleyata behaves as a simple mendelian recessive both to the type 

 form and to var. lacticolo7\ A new variety, exquisita, which probably 

 contains both recessive factors, that for varleyata and that for lacticolor, 

 will be dealt with in a subsequent communication. 



2. The type grossulariata carries a factor L, which localises the 

 black pigment to the normal pattern. The factor I allows the black 

 pigment to spread until it almost covers the fore wings as in var. 

 Iiazeleighensis. This variation appears to behave as a recessive when 

 mated to type insects. It is inherited independently of the factor for 

 varleyata, but is often introduced by crossing this variety with dark 

 strains of grossulariata. 



3. A method is described by which the black pattern can be 

 measured, and its area expressed as a percentage of the total extent 

 of the fore wings. The values of the black pattern in several families 

 were obtained, and were plotted as distributions and as percentage 

 frequency distributions, 



4. These diagrams show that in certain families the amount of 

 black in both sexes is considerably greater than in the type form, and 

 that the darkest parents have as a rule darker offspring than lighter 

 parents. Moreover, the percentage of black in the (/c/* is considerably 

 greater than in the $ $ , suggesting that femaleness or some factor 

 associated with it prevents the full development of the pigment. 



5. The size of the white collar in var. varleyata varies considerably. 

 This is possibly in some way connected with the factor I, for measure- 

 ments of one family show that the ? $ have slightly less white than 

 the (/(/, but the amount can scarcely be considered significant. 



6. A variety showing a fluctuating amount of white radiation on 

 the black ground of varleyata has been found, which appears to be 

 linked to the male in a manner analogous to that in which lacticolor is 

 linked to the female. At first sight it appears that this white radiation 

 should be part of the dominant white ground o^ grossulariata. Never- 

 theless, there seems to be some evidence to show that it is recessive to 

 varleyata. Since this radiation is a modification of the black ground, it 

 is clear that it cannot show in grossulariata insects, even if they carried 

 the factors necessary to produce it. The ratio of one radiated </ to 



