Here, again, the calculated results accord with those of experiment. Lastly, we may examine what should happen when the F_1 female is crossed with the _lacticolor_ {104} male. The F_1 female, owing to the repulsion between F and G, produces only the two kinds of ova Fg and fG, and produces them in equal numbers. Since the _lacticolor_ male can contain neither F nor G, all of its spermatozoa must be fg. The results of such a cross, therefore, should be to produce equal numbers of the two kinds of zygote Ffgg and ffGg, _i.e._ of _lacticolor_ females and of _grossulariata_ males. And this, as we have already seen, is the actual result of such a cross. Before leaving the currant moth we may allude to an interesting discovery which arose out of these experiments. The _lacticolor_ variety in Great Britain is a southern form and is not known to occur in Scotland. Matings were made between wild Scotch females and _lacticolor_ males. The families resulting from such matings were precisely the same as those from _lacticolor_ males and F_1 females, viz. _grossulariata_ males and _lacticolor_ females only. We are, therefore, forced to regard the constitution of the wild _grossulariata_ female as identical with that of the F_1 female, _i.e._ as heterozygous for the _grossulariata_ factor as well as for the factor for femaleness. Though from a region where _lacticolor_ is unknown, the "pure" wild _grossulariata_ female is nevertheless a permanent mongrel, but it can never reveal its true colours unless it is mated with a male which is either heterozygous for G or pure _lacticolor_. And as all the wild northern males are {105} pure for the _grossulariata_ character this can never happen in a state of nature. [Illustration: FIG. 19. Scheme illustrating the result of crossing a Silky hen with a Brown Leghorn cock. Black sex signs denote deeply pigmented birds, and light sex signs those without pigmentation. The light signs with a black dot in the centre denote birds with a small amount of pigment.]