428 Studies in the Theory of Descent. 



Carpini only in not being sexually dimorphic. 

 In Carpini the male possesses a far more brilliant 

 colouring than the female, the latter agreeing so 

 completely with the female of Spini that it can 

 hardly be distinguished therefrom, especially in 

 the case of the somewhat larger South European 

 specimens of the last species. Now as the more 

 simple colouring of the female must in any case be 

 regarded as the original form, we must consider 

 Spini, both sexes of which possess this colouring, 

 to be phyletically the older form, and Carpini, the 

 male of which has become differently coloured, 

 must be considered as the younger type. This 

 completely accords with the characters of the 

 larvre. 



I must here mention that I have also asked 

 myself the question whether the variations of the 

 different larval stages are connected together as 

 cause and effect whether the lightest specimens 

 of the fifth stage may perhaps not also have been 

 the lightest individuals of the third and fourth 

 stages. 



Such relationship is only apparent between the 

 third and fourth stages ; the darkest larvae of the 

 third stage become the darker varieties of the 

 fourth stage, although it is true that the lighter 

 forms of the third sometimes also become dark 

 varieties in the fourth stage. Between the fourth 

 and fifth stages there is scarcely any connection of 

 this kind to be recognized. Thus, the* darkest 



