2 24 Annals Entomological Society of America [Vol.11, 



Phar.macoi'Hagus (Papilio) philenor L., as a Model for 

 Mimicry in North America. 



Pharmacophagiis is a tropical assemblage, but a few species 

 have found their way into the northern belt in both the Old 

 World and the New. Pharm. polydamas, with an immense range 

 in South and Central America, also extends into the northern con- 

 tinent but does not there become the object of Mimicry. Pharm. 

 philenor, ranging through Mexico and the United States (except 

 the central district from Colorado northwards) but only as a 

 straggler in New England and southern Canada, is on the other 

 hand an important model for Mimicry. 



There is here no such interesting history of past migrations 

 to unfold as we were able to trace in the American Danaidas. 

 Ph. philenor is a member of the distinctively New World species 

 of Pharmacophagus associated together and separated from the 

 Old World species by structural characters. Rothschild and 

 Jordan state that every species can be recognized as American 

 by the examination of a single joint of one leg, and they are 

 therefore justified in concluding that all the New World species 

 were derived from a single ancestor possessing this character. 

 There is no sufficient evidence that any of the numerous patterns 

 are ancestral as compared with the others, although it is tolerabh' 

 safe to conclude that the presence of hind-wing "tails" is primi- 

 tive as compared with their absence. Following this indication, 

 we find that as a general rule the specialized and modem forms are 

 predominant nearer to the Equator, the comparatively ancestral 

 tailed forms occurring in latitudes more remote from it both north 

 and south. 



Ph. philenor is a "tailed" form, although its sub-species or sua 

 in the Tres Marias Islands is nearly tailless. It is probably an 

 intruder into North America from the tropics of the same Conti- 

 nent. It is well known to possess the characteristics of distaste- 

 ful species^gregarious larvae, tenacity of life, and a strong, dis- 

 agreeable scent. 



The Three Papilio Mimics of Ph. philenor in North 



America. 



The three swallow-tail mimics of philenor belong to separate 

 groups of Haase's section Papilio. All of them range from the 

 Atlantic to the Mississippi basin. 



