. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. 82 THE ORIGIN OF GYNANDROMORPHS. or whether, owing to the striking character of their wings, they have more often attracted attention, is perhaps open to question. The dif- ferences between the coloration of the males and females in some species would at once arrest attention. On the other hand, in certain species and in certain hybrid combinations the number of gynandro- morphs is so great that there can be little doubt that their occurrence here is directly related to the specific or
. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. 82 THE ORIGIN OF GYNANDROMORPHS. or whether, owing to the striking character of their wings, they have more often attracted attention, is perhaps open to question. The dif- ferences between the coloration of the males and females in some species would at once arrest attention. On the other hand, in certain species and in certain hybrid combinations the number of gynandro- morphs is so great that there can be little doubt that their occurrence here is directly related to the specific or to the hybrid nature of the insects. Eleven more gynandromorphs of Argynnis paphia added by Wenke brings the total to nearly 1,000. In regard to the chromosomal background, the situation is the converse of that in Drosophila and in nearly all other insects. The male has two sex chromosomes (text-fig. 65), which may we call ZZ, and the female one, Z, and another called W, corresponding to the Y of Drosophila. The genetic evidence in the case of Abraxas makes this view highly probable, and Seller has shown in another moth that there is, in fact, such a chro- mosomal difference between wz zz the female and the male. As has been stated, in Dro- sophila the female combina- tion XX is the basis for most of the gynandromorphs be- cause the combination al- lows, through the elimina- tion of one of the X's, the formation of parts with one X which is male. By anal- ogy we should expect in Lepidoptera that the male combination ZZ would furnish the basis for the gynandromorphs of this group, since through elimination of one Z the female condition w^ould arise. The most interesting case in the Lepidoptera is tliat of a hybrid gynandromorph in the silkworm moth, because here we know the genetic relation of the factors involved. Toyama obtained two bilateral gynandromorph caterpillars whose mother belonged to a race with a striped ''zebra" pattern in the caterpillars and whose father bel
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