ABSTRACT
Whilst conducting biological experiments on parthenogenesis in saw-flies during the year 1923, the writer obtained two males and an intersex-like specimen of the species Pristiphora pallipes, Lep., under somewhat peculiar circumstances. As this species appears almost completely thelytokous—the males being exceedingly rare—and as sexual abnormalities in it have never been observed before, and indeed, have only been recorded eight times previously among the Tenthredinidæ, opportunity is here taken of describing and discussing these special appearances. It will be necessary first to dwell upon the experimental conditions as it is not improbable that they may have had a direct bearing upon the results obtained, but in any circumstances the results are of interest in themselves.
I am indebted to Miss A. Betts, B.Sc, for information concerning the ontogeny of the internal genitalia of the honey-bee.
Nurse cells in saw-flies have npt been described yet; the writer found such two years ago but description is withheld for a cytological paper now in preparation.
As the homogametic sex is the female, XX, in hymenoptera, it can hardly be assumed for a parthenogenetic species that the male is constituted XY, unless it be assumed that Y is a fragment of X, a phenomenon which has not been observed.
