MIMICRY IN BOREAL AMERICAN BHQPALOCHIA. 19 



t 



Archippus is said to be derived from an ancestral form, arthemis. Arthemis and 

 weidemeyeri have flourished prosperously in the struggle for existence, and it is 

 difficult to understand why archippus should be so specially favored. The 

 statements attempting to prove the evolution of archippus from an ancestral 

 form (arthemis) seem to me to be very inconclusive. 



How can we explain the color resemblance of floridensis to berenice and 

 obsoleta to strigosaf 



The butterflies that have a range from north to south on the Atlantic slope, 

 are generally larger and darker in color in the south. The Arctic form of Papilio 

 glaums is only about half the size of the Florida form. The Florida forms of 

 troilus and polyxenes are also larger than in the north. In the Orthoptera the 

 individuals of species having a northern and southern range are larger in the 

 south and their colors are more decided. This is also true of birds and probably 

 also in mammals. In the desert country (Utah and Arizona) in which obsoleta 

 and strigosa fly, species having any considerable range are paler in color in the 

 desert. This applies to birds and mammals also. In mammals the intense sun- 

 light often causes a physical bleaching of the hair. Similar environmental con- 

 ditions explain these color resemblances better than the hypothesis of mimicry. 



American entomologists have not taken up the study of mimicry to any great 

 extent and it is hoped that those persons interested in the subject on this side 

 of the Atlantic will make accurate observations that will be of value in solving 

 theae questions. At present I take the view that there is not enough evidence 

 to substantiate the hypothesis of mimicry in North American butterflies. The 

 objections to the hypothesis are not to be ignored. 



1. Bates, G. L 



LITERATURE 



1912. Ibis, 9th ser., V, 630-631. 



2. McAtee, W. L. 



1912. Auk, 119-120. 



3. Marshall, Guy A. K. 



1909. Trans. Ent. Soc. Lond., 329-383. 



4. PoULTON, E. B. 



1909. Ann. Ent. Soc. Amer., II, 203-242. 



5. Rothschild and Jordan. 



1906. Novitates Zoologica, XIII, 411-472. 



6. Wright, W. G. 



1905. The Butterflies of the West Coast, p. 30. 



7. Packard, A. S. 



o tt 1904 ^ Proc * Amer - PhiIos - Soc., XLIII, 393-450 



o. Haase, Erich. 



1893. Bibliotheca Zoologica, III, 1-120, 1-161. 



9. SCUDDER, S. H. 



m t^ 1889 * 5. ut terflies of Eastern U. S. and Canada, : 



10. Edwards, W. H. 



1884 



11. Gentry, T. G 



lurnus 



1876. Life Histories 



12. Barton, B. S 



an Essay towards a Materia Med 



