40 rUOCEEDIXGS OF TUB 



nuniolic |):ilter)i lias been analysed* by the |)rp,sent writer, wlio 

 lias coiii|)!ircHl its elements with tliose ot" the commonest non- 

 mimetic JS'. Amt^riciui Limcaitis. The general results of the 

 comparison are brielly stated below: — 



" 'IMie diiference between the pattern of tlie mimic {Limoiitu 

 arcJtii>pns] and that of its nan-mimetic parent [/^. artJi-cinis] is 

 enormous - ])robably as great as that between any two butterflies 

 in the world ; but the steps by Avhich the transition was effected 

 were long ago suggested by S. H. Scudder .... ''t. 



" A careful comparison between arthemis and arcliippus reveals 

 the most conclusive evidence of selection. The one species lias 

 become changed into the other precisely as if an artist were to 

 paint the pattern of archippns upon the wings of arihemis, 

 retaining unchanged every minute i)art of the old markings that 

 could be worked into the new, and obliterating all the rest. 

 Thus, extending in this direction and wiping out in that, the 

 great transformation has been effected and one of the most 

 beautiful mimics in the world produced '" J. 



Professor J. 1\ Abbott has recently criticised § these conclusions 

 or rather his own inference from them — an inference which I 

 am very far from accepting. Professor Abbott takes as his basis 

 the following statement of the selectionist principle as applied 

 to these superficial resemblances: — "In miu)icry the selecting 

 influence ot the model, if we may use such a term, will be con- 

 stantly operative upon all individuals of the mimicking species 

 \\herever the two are associated in the same habitat " (p. 208). 

 These words are an overstatement, for the selectionist does not 

 claim an influence upon every individual. Exceptional failures in 

 the mimetic likeness may and do survi\e even when the model 

 is abundant ||. But it is the following inference from the state- 

 ment which is especially open to criticism — " it would seem 

 ])i-obable therefore, in the case under discussion, that in the 

 districts where Anosia [the model] and L. arthemis [the hypo- 

 thetical non-mimetic ancestor of the mimic] occur together, the 

 hitter would constantly show in some way the influence of the 

 selective factor. Even if no incipient L. arcMppus is to be found, 



* Trans. Eiit. Snr. Land., 1908, pp. 447-488. 



J7in. E»t. Soc. Amcric({, ii. 19(H), pp. •20.3-242. Also pul)li.'^Iiecl in 

 "Darwin anrl tlie Origin," Ijondon, 11)09, ])p. ]44-l*]2. 



Vroc. Acad. Nat. Set. I'hilad., Jan. 1914, pp. lGl-194: issued Apr. 21, 

 1914. 



t " Darwin a'ul the Origin." p. ](>'). 



I " Darwin and tl)e Origin." pp 16."), IGG. 



§ "Mimicry in tlie genua Linienitis with t-special reference to the ' Ponllon 

 liyjifitlie.'^is'.' " Washinyfoii Uiiiv. Studies, vol. i. I't. I, no. 2, Jan. 1914, 

 ])']<. 2().S-221. 



II Kiinierons instances might be given. One of the best lias been already 

 described in the non-mimetic dioiii/sn.s form of P. dardaniis on the W. Coast, 

 of Africa (sec pp. 43, 44). No doubt " the selecting influence of the model" 

 keeps I lie mimetic female forms oi dardanus common, while the absence of a 

 inodfl l;e<'])S dio)ij/si/.< rare, but it does not prevent the existent? of this latter 

 form or of the very rare non-miiiiel ic ti'iijhi form in Xatul. 



