68 Studies in the Theory of Descent. 



wherever they occur, and which, nevertheless, 

 appear in different climates as climatic varieties. 

 This is the case with Pararga SEgeria (Fig. 23, 

 Plate II.), the southern variety of which, Meione 

 (Fig. 24, Plate II.), is connected with it by an 

 intermediate form from the Ligurian coast. This 

 species possesses, therefore, a decided power of 

 responding to the influence of temperature, and 

 yet no distinction has taken place between the 

 summer and the winter form. We can thus 

 only attribute this different deportment to a 

 different kind of heredity ; and we may therefore 

 plainly state, that changes produced by alternation 

 of climate are not always inherited alternatingly, 

 i. e. by the corresponding generations, but some- 

 times continuously, appearing in every generation, 

 and never remaining latent. The causes which 

 determine why, in a particular case, the one 

 or the other form of inheritance prevails, can 

 be only innate, i. e. they lie in the organism 

 itself, and there is as little to be said upon 

 their precise nature as upon that of any other 

 process of heredity. In a similar manner Darwin 

 admits a kind of double inheritance with respect 

 to characters produced by sexual selection ; in 

 one form these characters remain limited to the 

 sex which first acquired them, in the other form 

 they are inherited by both sexes, without it 



cable to the female sex. There exists in this species a trifling 

 sexual dimorphism, but no seasonal dimorphism. 



