Mimetic Patterns to fho Original Form. 73 



Pierine imitators. What is the meaning of this coinci- 

 dence ? The first answer that suggests itself is that it is 

 simply an ordinary case of mimicry ; the red spots belong 

 originally to the Ileliconiiis, and the Pierine has acquired 

 similar spots in order to complete the mimetic picture. 

 Two facts, however, militate against this supposition. 

 The first is that these red patches, so far from being 

 confined to the mimicking Pierines, are found to have 

 a very wide distribution throughout the whole Pierine 

 subfamily, existing not only, as we have seen, in non- 

 mimetic neotropical forms such as Plerls locusta and 

 P. phaloe, but in numerous old-world genera as well, 

 reaching a great development in the Indian and Austra- 

 lian Delias, and having even left a relic in the common 

 white butterflies of our own country. It would be extra- 

 vagant to suppose that these widespread characters owe 

 their origin simply to the necessity for mimicking certain 

 South American Heliconii. Moreover, as I have else- 

 where shown, such an origin for the old-world forms as 

 this hypothesis would involve is at variance with what is 

 known of Pierine phylogeny. The second fact is that 

 although several Beliconii which are not the subjects of 

 mimicry show marks of the kind, yet they are most con- 

 stant, most distinct and most Pierine-like in species of 

 Heliconius that serve as models. There must, it would 

 seem, be a relation between the two forms which is not 

 entirely due to mimicry by the Pierine. Are we then to 

 say that the Heliconius is the mimic and the Pierine the 

 model ? This would appear to be going against all 

 received ideas on the subject, and to be negatived by all 

 that is known of the inedible qualities of Heliconius and 

 of the ancestral coloration of the Pierines ; nevertheless, 

 with respect to the particular marks in question I believe 

 that it comes near to the true expression of the fact, and 

 I -would suggest that the key to the difiiculty is to be 

 found in the following considerations. 



It has been well shown by Fritz Miiller,* whose con- 

 clusions have been followed and amplified by Meldola and 

 Poulton, that there exist two kinds of mimetic associa- 

 tions — in one of which an edible form shelters itself by 

 resemblance to another form well known to be inedible, 

 this being the aspect of mimicry first detected and 

 explained by Bates ; while in the other a group is 

 constituted all of whose members are inedible, and join 



* " Kosmos," 1879, p. 100. 



