I.S8 



Appendix. 



naturalists would have to devote their whole time and 

 energy to the order Lepidoptera, which I have been 

 unable to do. 



From the considerations offered, it thus appears that 

 the phenomena of seasonal dimorphism may depend on 

 extremely complex processes, so that one need not be 

 surprised if only a few cases now admit of certain 

 analysis. We must also admit, however, that it is more 

 advantageous to science to be able in the first place to 

 analyze the simplest cases by means of breeding experi- 

 ments, than to concern oneself in guessing at cases 

 which are so complicated as to make it impossible at 

 present to procure all the materials necessary for their 

 solution. 



