269 



bc found again in just the saine way in a system of the larvae, 

 or in other words: the relation of forms of the caterpillars must 

 liai'nionise precisi'ly witli that of the butterflies." 



„If the deveh)pnient is only the reaction of the specific orga- 

 nisni to the influence of the outer circumstances, dissimilarities 

 in the phyletlc development of the different stages of lif(; might 

 be expected" ... A congruency might be the consequence of 

 correlation. 



"VVeismann goes on to say (1. e. p. 157) "that the primitive 

 cause of variations when coming fi'om outer circumstances must 

 occur far oftener with larvae than with butterflies." 



Darwin points out the heridity in corresponding ages or as 

 Haeckel calls it: homochronic heridity. 



Weismann thinks he has here found an explanation for the great 

 differences between larva and imago (p. 168) „as the acquirements 

 of the separate stages in the following generations are al way s 

 transferred to those stages themselves but the other stages remain 

 untouched". 



After having discussed the different families, to which I shall 

 return later on in discussing the groups, Weismann comes to the 

 following conclusion: „there is a great congruency between the 

 system of larvae and that of imagines, especially where the genera 

 are concerned, but the incongruencies appear mostly with varieties 

 and families". To the questions, what may be the cause of the 

 difference in form of butterflies and moths being so much greater 

 than that of their caterpillars, and why the imagines of the 

 Rhopalocera have so many characteristics in common which their 

 caterpillars do not possess, Weismann gives the following answer 

 (1. c. p. 195) : „that this might be explained by the great differences 

 in the manner and duration of life of the imagines." 



Weismann's study was foliowed by a great many others, some 

 of which I intend to discuss with the families. Here I will only 

 give a short index of those which are of general importance. 



Wilhelm Muller is the first (1886) who pays special attention 



