The Cause of Gynandromorphism in Insects

IN recent years many cases have been recorded in the group of insects in which parts of the body show the characters of the male and other parts those of the female. Most frequently the separation lies along the middle line of the body, so that one side is like the male and the other like the female. About two years ago I attempted in the case of the bee to correlate this result with the well known frequency of dispermy of the insects' egg.' Two' spermatozoa having entered, one fuses with the egg nucleus and its products produce the female characters; the other develops alone and gives the characters of the male to the parts of the body it supplies with nuclei, etc. That the latter assumption is not arbitrary is shown by experiments with the egg of the sea-urchin in which it has been possible to fertilize a non-nucleated piece of the egg with a single spermatozoon. Boveri has attempted to prove that under these conditions the characters of the larvae are paternal, which is in accord with our hypothesis for the bee. The evidence however on which Boveri's conclusion rests has been disputed. More recently Godlewski has succeeded in cross-fertilizing a non-nucleated fragment of the egg of a sea-urchin with the sperm of a crinoid. The characters of the young larvae are said to be maternal, indicating that the protoplasm rather than the nucleus is the controlling factor in determining the characters, but Godlewski's statements apply only to the very earliest stages of development, where according, to Driesch's results the maternal influences predominate. A test of the view that I have suggested should be found for the bee if a gynandromorph should arise in a cross between two species;, for, on mly hypothesis those parts that develop from the combined nuclei should be female and hybrid in character, while those that com-ie from the single nucleus of the spermatozoon should be male