200 MIMICRY IN N. AMERICAN BUTTERFLIES 



of the most interesting and instructive examples 

 of Mimicry in the world. Its value will lie in 

 the early stage reached by the resemblance, to- 

 gether with the diminution of the likeness in 

 californica to the south and, especially, in lorquini 

 to the north. There is no reasonable doubt that 

 lorquini forms a single Syngamic community 

 along the Pacific coast of North America, and 

 we should therefore witness, first, the marked 

 strengthening of characters in an area of selec- 

 tion; secondly, their transmission with diminished 

 effect into other areas. 



If what I have observed be the phenomena 

 presented by the growth, at an early stage, of 

 a mimetic likeness in lorquini, then that growth 

 is ' continuous ' and transitional to the last and 

 finest degree. 



It is perhaps appropriate to state in a few lines 

 how we may imagine that the selection of minute 

 characteristics such as the presence or the position 

 of a single spot may be made. We ourselves 

 may observe that one individual butterfly is a 

 better mimic than another. We may then 

 analyse the pattern, as I have attempted to do 

 in this address, and realize that the improvement 

 is due to differences in one or more relatively 

 minute elements. Eecognizing the cause of the 

 change, we are perhaps prone erroneously to 

 suppose that enemies recognize it also and that 

 selection has been brought to bear directly and 

 consciously upon it. Such a view is almost cer- 



