THE HORMONE THEORY 159 



male characters, and in the females the only difference 

 was that some of them were slightly darker than the 

 normal. Meisenheimer and Kopc^ after him claim 

 to have grafted ovaries into males and testes into 

 females, with the result that the transplanted organs 

 remained alive and grew, and in some cases at least 

 became connected with the genital ducts. Even in 

 these cases the moth when developed showed the 

 original characters of the sex to which belonged 

 the caterpillar from which it came, although it was 

 carrying a gonad of the opposite sex. It will be seen 

 that these results are the direct opposite of those 

 obtained bv Steinach on Mammals. We have no 

 evidence that the darker colour of the normal male 

 in this case is adaptive, or due to external stimuli, 

 but the feathering of the antennae is generally 

 believed to constitute a greater development of the 

 olfactory sense organs, and is therefore adaptive, 

 enabling the male to find the female. This is 

 therefore the kind of organ which would be expected 

 to be affected by hormones from the generative 

 organs. It is stated that the sexual instincts were 

 also unaltered, a male containing ovaries instead of 

 testes readily copulating with a normal female. 



These results, almost incredible as they appear, are 

 in harmony with the relatively frequent occurrence 

 of gynandromorphism in insects.^ One of the most 

 remarkable cases of this is that of an ant {Myrmica 

 scahrinodis) the left half of which is male, the right 

 half not merely female, but worker — that is, sterile 

 female, without wing. Cases in Lepidoptera, e.g, 

 Amphidasys betularia, have frequently been recorded. 



* See Doncaster, Determination of Sex (Camb. Univ. Press, 1914). 

 chap. ix. 



