No. 600] 



EXPERIMENTAL INTERSEXUALITY 



713 



intersexual females appear which are more than half-way 

 between males and females. The secondary sex-char- 

 acters are almost male. The instincts and behavior are 

 about intermediate between the sexes. Males are 

 scarcely attracted or not at all and no mating occurs. 

 The copnlatory organs show the strangest combinations 

 of the male and female types, but there are still typical 

 but rudimentary ovaries left. There is now another 

 Japanese race in my possession, the race X. This one 

 exhibits a still higher potency of the male factor M. If 

 we cross this one with the European race F, a still higher 

 degree of inter sexuality appears. Now we have animals 

 which externally are almost indistinguishable from true 

 males. But certain characters, especially in the copular 

 tory organs, still show their female origin. The instincts 

 are entirely male and they try — always unsuccessfully — 

 to mate with females. But the most interesting feature 

 is the sex gland. This is a body looking externally like 

 a testis, but showing in sections every single step between 

 an ovary with nothing but immature eggs through a 

 mixture of ovarial and testis tissue to a real testis. This 

 is of course the highest grade of intersexuality which can 

 be reached. The next step would be the complete trans- 

 formation of the would-be females into males. And this 

 can be obtained too. I have two Japanese races and 

 A which show such a high potency of M that crossed with 

 any European females and the Japanese females H they 

 produce nothing but males, all would-be females being 

 converted into males. 5 



the wings. In one line intersexuality begins with, white wings, then dark 

 cunei appear on the wings; they grow larger and larger, forming streaks 

 along the veins until finally only fine white spots are left on a dark wing. 

 The second series shows even in the first grades of intersexuality male color 

 all over the wings without any streak formation. Which type appears 

 depends on both races involved, and is due to physiological conditions in 

 regard to pigment formation which are not yet entirely clear. The inter- 

 sexual males always exhibit the first type. Color photographs of an almost 

 complete series of the second type are given in my papers from 1912 and 

 1914. Photographs of the first type in the female series are not yet pub- 



