A FURTHER CONTRIBUTION TO THE THEORY OF 



SEX 



RICHARD GOLDSCHMIDT 



Kaiser-Wilhelm-Institut fiir Biologic, Berlin 



FIFTY-THREE FIGURES 



In a series of papers published during the last five years we 

 have dealt with the interesting phenomenon of experimental in- 

 tersexuality, produced by crossing different geographic varieties 

 of the gypsy-moth, Lymantria dispar L, Many of the facts, 

 as well as their theoretical explanation, have been summarized 

 in a recent paper in the American Naturalist. ^ As it will prob- 

 ably be some time before a monographic account of this work, 

 containing all the experimental details, can be published, we 

 wish in this paper to communicate some more facts as well as 

 the theoretical considerations to which our work has led. 



We must briefly remind the reader of the principal facts and 

 their explanation. It was shown that by crossing different 

 European and Japanese races of gypsy-moths, very different 

 results can be obtained. Some crosses yield normal offspring, 

 but, in others the individuals of one sex assume, to a certain ex- 

 tent, the characters of the other sex — they become intersexual. 

 This result proved to be a constant one for definite combina- 

 tions. Further, the degree of intersexuality was constant in a 

 given cross, but could vary, in different crosses, throughout the 

 entire range of possibiUties between maleness and femaleness, 

 the extremes being, of course, the complete transformation of all 

 females into males or vice versa. This transformation occurred 

 in regard to secondary as well as to primary sex-characters. 



1 Experimental intersexuality and the sex-problem. Amer. Natur., v. 50. 1916. 



593 



