Inheritance and Sex in Abraxas grossulariata

Abstract

IN February, 1906, in conjunction with the Rev. G. H. Raynor, I gave a paper to the Zoological Society on the inheritance of a variety of the moth Abraxas grossulariata and its relation to sex (Proc. Zool. Soc, 1906, vol. i., p. 129). We found that when the var. lacticolor (flavofasciata) was crossed with the type it behaved as a Mendelian recessive, disappearing entirely in generation F₁. When two heterozygotes were mated together, var. lacticolor reappeared, but only in the female sex, roughly half the females and all the males being typical. When a heterozygous male was mated with lacticolor female, the variety appeared in both sexes in the offspring, viz. in about half the males and half the females. When, however, a lacticolor male so produced was paired with a heterozygous female, we found that all the males were typical and all the females lacticolor. This result was given in our paper with some hesitation, since it was founded on a rather small number of specimens (29 O, 11 O+ ), but this year it is amply confirmed. I have reared 116 males and 74 females from six families of this mating, and every male is typical, every female lacticolor. Mr. Raynor has also reared equally large numbers with the same result. From a family of the converse cross, on the other hand (lacticolor O+ X heterozygous O), I have reared 24 type O, 22 lacticolor O, 17 type O+, 18 lacticolor O+, a fair approach to the expected equality in each sex.