126 MIMICRY IN BOREAL AMERICAN RHOPALOCERA. 



influence is seen in Limenitis astyanax, a secondary mimic of the three mimics 

 of philenor. Astyanax is a black butterfly with a greenish or bluish luster and 

 has the border of the wings marked with bluish or greenish spots. If the state- 

 ment be true both sexes needed protection, as they are alike in appearance. 



This idea could be carried still further by citing Limenitis arizonensis as a 

 mimic. It is a species found in Arizona and northern Mexico. Poulton further 

 declares that one of the most interesting elements in this complex mimetic system 

 is the final appearance of a tertiary mimic of astyanax, the female of Argynnis 

 diana. He need not have stopped here as the female of nitocris is also blue- 

 black. In the greater number of species of Argynnis there is no antigeny and 

 some observers hold that the antigenetic females of diana are ancestral forms 

 (primitive) . This would not be consistent with the theory of protective mimicry 

 as the so-called mimics would be the more recent forms, as influenced by the 

 models. The species in the genus Argynnis in North America that show marked 

 sexual diversity are diana, idalia, nokomis, leto, nitocris, and cybele. In the female 

 of idalia there is a double row of cream-colored spots on the secondary wings and 

 in the male one of the rows of spots is red or tawny. The female nokomis is 

 brown and buff and the females of leto are brown and buff. The female of cybele 

 is generally normal (like the male), but in some instances is brown and buff, 



much resembling the female of leto. 



The female of nitocris, as mentioned, is blue-black. I believe the antigeny 

 in these species is due to a general law not understood. It does not seem con- 

 sistent to pick out one species (diana) and say that its antigeny is due to tertiary 

 mimicry. How can the dimorphism of the other species be explained? The 

 theories in regard to the resemblance among our butterflies are very ingenious 

 but the evidence or proof so far advanced seems inadequate. It will be neces- 

 sary to show that butterflies are commonly used as food by birds; that the 

 bodies of some species of butterflies are nauseous to birds; that the birds are 

 unable to distinguish by sight between edible and non-edible species, if there are 

 two classes, and that antigeny is brought about in all cases or at least m some 

 by protective resemblance. 



There is a striking resemblance between the butterflies Limenitis archippus 

 (disippus) and Anosia plexippus. Professor Poulton speaks of archippus as the 

 beautiful mimic of A. plexippus. The protective idea in this case is the same 

 as in the so-called pharmacophagus butterfly, the imago of plexippus which is sai 

 to be repugnant to birds but the repugnance is not based on the idea of t e 

 butterfly feeding on a poisonous plant (Asclepias) in the larval stage. 



There are two other species in the genus Limenitis that have been considere 

 to be races or tophomorphs by some and valid species by others. They ar 

 fioridensis Strecker and obsoleta (hulsti) Edw. The former is found in southern 

 Florida and the latter in Arizona and Utah. Fioridensis is considerably dafK 

 in color than archippus, and obsoleta is lighter in color than the latter. Floridensi^ 

 is said to mimic Anosia berenice, and obsoleta is supposed to mimic Anosia stngos . 



