2 28 Annals Entomological Society of America [Vol. II. 



The evolution of astyanax from arthemis was far simpler than 

 that of archippus. The great difference in appearance between 

 parent and offspring is brought about, as regards the upper sur- 

 face, by the disappearance of the broad white band of arthemis 

 together with all but a trace of the sub-apical white markings of 

 the fore wings. Over and within the area formerly occupied by 

 the white band, a bluish or greenish iridescence spreads from the 

 marginal region where it exists in arthemis. This marginal irides- 

 cence — just as in astyanax — is bluish in some individuals of arthe- 

 mis, greenish in others. Reddish sub-marginal spots, although 

 rarer in the hind wing of astyanax, are actually commoner in 

 the fore wings than in arthemis. This curious fact, together 

 with the evidence that astyanax and archippus may occasionally 

 interbreed, suggests the possibility of some connection between 

 the origins of the two mimics. 



The under surface of astyanax has not only similarly lost the 

 white markings, but the chocolate-brown ground-colour of arthe- 

 mis has become transformed into a lark iridescent greenish- 

 brown. Against this background the reddish spots near the 

 margin and base of the wings become far more conspicuous than 

 in the parent form. The material for this transformation in tint 

 is still to be seen in the great variation of the ground-colour in 

 arthemis. 



Although, as Scudder rightly maintains (1. c. 287), L. astyanax 

 is a very poor mimic of Pharm. philenor, it bears considerable 

 resemblance to the three Papilio mimics, especially troihis. 

 Although the iridescent blue or green of its upper surface ap- 

 proaches rather more closely than the Papilios to the brilliant, 

 steely lustre of philenor, it is still in this respect widely separated 

 from the primary model and near to the mimics. The reddish 

 spots of the under surface offer but a rough likeness to those of 

 any of the above named species, but there can be no doubt that 

 their emphasis is an element in the mimetic resemblance. 



A careful examination of large numbers of astyanax from the 

 extreme south of the range where it passes out of the area of 

 glaucus and troihis but remains within that of philenor and aster- 

 ius, might yield interesting results. An investigation of the pro- 

 portion it bears to the four Papilio nidae in various parts of their 

 common range would also be of deep interest. Of the highest 

 importance would be the attempt — which would probably be 

 successful — to breed astyanax and arthemis and to ascertain 



