Phyletic Parallelism in M clamor pkic Species. , 507 



stage does not attain to this high rank. Such a 

 condition appears especially complicated when the 

 two stages can again be formed into groups of a 

 still higher rank. 



This is the case in the tribe Rhopalocera, which 

 is founded on the imagines alone, the larvae form- 

 ing only families of butterflies. Both stages can 

 however be again combined into the highest 

 systematic group of the Lepidoptera. 



In this case also the difference in the value of 

 the systematic groups formed by the two stages 

 corresponds precisely with the difference in the 

 conditions of life. This appears very distinctly 

 when there are several sub-groups on each side, 

 and not when, as in the fleas, only one family is 

 present as a tribe on the one side and on the 

 other as a family. Thus in the butterflies, on the 

 one side there are numerous families combined 

 into the higher rank of a sub-order (imagines), 

 whilst on the other side (larvae) a group of the 

 same extent cannot be formed. In this instance 

 it can be distinctly shown that the combination of 

 the families into a group of a higher order, as is 

 possible on the side of the imagines, corresponds 

 exactly with the limits in which the conditions of 

 life deviate from those of other Lepidopterous 

 families. The group of butterflies corresponds 

 with an equally large circle of uniform conditions 

 of life, whilst a similar uniformity is wanting on 

 the side of the larva:. 



