riiylctic Parallelism in Mctamorphic Species. 407 



extremely constant, are of great rarity. Vanessa lo 

 is a case in point, the pupa being light or dark 

 brown, or bright golden green, whilst in the two 

 other stages scarcely any light shades of colour or 

 variations in the very complicated marking are to 

 be met with. 



The facts thus justify the above view that the 

 individual stages of development change indepen- 

 dently that a change occurring in one stage is 

 without influence on the preceding and succeeding 

 stages. Were this not the case no one stage 

 could possibly become variable without all the 

 other stages becoming so. Did there exist a 

 correlation between larvae, pupae, and imagines of 

 such a nature that every change in the larva 

 entailed a corresponding change in the imago, as 

 soon as a large number of larval characters became 

 fluctuating (i.e. as soon as this stage became 

 variable), a large number of imaginal characters 

 would necessarily also become fluctuating (i.e. 

 this stage would also become correspondingly 

 variable). 



There is one other interpretation which might 

 perhaps be attempted from the point of view of 

 the old doctrine of species. It might be said that 

 it is a special property of certain larval or imaginal 

 markings to be variable whilst others are constant, 

 and since the larval and imaginal markings of a 

 species are generally quite distinct, it may easily 

 happen that a butterfly possessing markings having 



