IV] NEW-WORLD MIMICS 47 



for two Nymphaline butterflies in the United States. 

 One of these is the large Fritillary Argynnis diana 

 of which the dark female has a markedly blue tint 

 on the upper surface (PI. XVI, fig. 3). The other 

 is a Limenitis^ related to our own White Admiral. 

 This form, L. astyanax (PI. XVI, fig. 5), is a dark form 

 with a bluish iridescence on the upper surface. It is 

 found, like P. philenor, over the greater part of the 

 Eastern States, while to the north, near the Canadian 

 boundary, its place is taken by L. arthemis with 

 prominent white bar across both wings (PI. XVI, fig. 4). 

 There is reason for believing that where the two overlap 

 there is occasional inbreeding, and that the hybrid 

 is the form known as proserpina, resembhng astyanax 

 more than arthemis. It must be admitted that in 

 general appearance L. astyanax and Argynnis diana 

 are more like Papilio troilus than P. philenor. In 

 explanation it has been suggested that all the mimics 

 are on the way to resembling P. philenor, and con- 

 sequently we should expect them at certain stages 

 to shew more resemblance to one another than to 

 the form they have all as it were set out to mimic. 

 On this view they wiU all arrive at a close resemblance 

 to philenor in time. Another explanation is that 

 favoured by Professor Poulton on which it is assumed 

 that we are here dealing with a case of Mullerian 

 Mimicry, all of the species in question being distasteful 

 with the exception perhaps of A. diana. Thus troilus 

 and astyanax though distasteful are less so than 



1 The N. American members of thia genus are often referred to aa 

 Basilarchia. 



