A Female Intermediate Between Papilio Glaucus and Its Form Turnus (Lepid.: Papilionidæ)

It is well known that there are two forms of female in Papilio glaucus Linn., the black type form and the yellow form turnus Linn., and that they are not only sexual forms, but geographical as well. In the southern part of the range of this species, black females are the rule, while in the north, only yellow ones occur; in a considerable region near the middle of its territory, both forms fly together. Missouri is in that intermediate region, though collectors in the neighborhood of St. Louis consider the yellow form somewhat scarce. The males are invariably yellow, and a few closely related species that inhabit the southwestern part of the country and northern Mexico are never black in either sex. To the knowledge of the writer, no breeding has been done in this species with a view toward working out the relations of these fo,rms in the light of genetics. The fact that this condition is linked with sex, and that according to Jordan there is a rarity of intermediate forms, indicates that this is a Mendelian phenomenon. Knowing of the rarity of intermediate forms, I was surprised to. take at Allenton, Missouri, on August 9, 1931, such a female, having the black color of glaucus, but heavily suffused with yellow on the upper and lower surfaces of both pairs of wings. This has the effect of making the black stripes very noticeable on the upper side, and in this respect the specimen differs markedly from glaucus. This specimen is in no wise comparable to one mentioned by