Phyktic Parallelism in Mctamorpkic Species. 401 



I. 



LARVA AND IMAGO VARY IN STRUCTURE INDE- 

 PENDENTLY OF EACH OTHER. 



IT would be meaningless to assert that the two 

 stages above mentioned were completely indepen- 

 dent of one another. It is obvious that the amount 

 of organic and living matter contained in the cater- 

 pillar determines the size of the butterfly, and that 

 the quantity of organic matter in the egg must deter- 

 mine the size of the emergent larva. The asser- 

 tion in the above heading refers only to the 

 structure ; but even for this it cannot be taken as 

 signifying an absolute, but only a relative inde- 

 pendence, which, however, certainly obtains in a 

 very high degree. Although it is conceivable 

 that every change of structure in the imago may 

 entail a correlative change of structure in the larva, 

 no such cases have as yet been proved ; on the 

 contrary, all facts indicate an almost complete in- 

 dependence of the two stages. 1 1 is quite different 

 with cases of indirect dependence, such, for example, 

 as are brought about by ' nurse-breeding.' This 

 phenomenon is almost completely absent in Lepi- 



D d 



