1909J Mimicry in the Butterflies of North America 207 



The western section of the Palaearctic Region is sharply cut 

 off by the Sahara from the Ethiopian, and its few examples of 

 Mimicry are not such as would be likely to awaken the interest 

 and enthusiasm of the beginner. The eastern Palaearctic section 

 sufTers from the opposite defect. Separated by imperfect bar- 

 riers from the Oriental Region, its butterfly fauna is complicated 

 by much invasion of specially protected species from the tropics, 

 and the examples of Mimicry are too numerous and too little 

 known. North America occupies a position conveniently inter- 

 mediate between the two sections of the Palaearctic portion of 

 the circumpolar land-belt. It has been invaded by models from 

 the eastern tropics of the Old World and also probably from the 

 tropics of the New; but the species are few and their eft'ects upon 

 the indigenous butterflies sharp and distinct. The Mimicry itself 

 aft'ords striking and remarkable evidence of the lines of migration 

 followed by some of the intruding models. The ancestral forms 

 from which the mimics were derived, have nearly always per- 

 sisted, and enable us to unravel the history of the change, with 

 exceptional clearness. The examples bear in a most interesting 

 manner upon the two great hypotheses associated respectively 

 with the names of H. W. Bates and Fritz Miiller. Although the 

 butterfly fauna is as well known as that of any part of the world, 

 the mimetic resemblances supply material for a large amount of 

 much-needed original investigation, inviting the attention of 

 American naturalists in almost every locality. 



The Danaine Models of North America, and Their Rela- 

 tionship TO THE South American and Old 

 World Danainae^ 



The Danainae are the most important and most extensively 

 mimicked of all specially protected butterflies in the Old World 

 tropics. The Acraeinae, so abundant in Africa, are also greatly 



- The subject of the address from this point onwards is treated in consider- 

 able detail in the author's memoir, Mimetic North American species of the Genus 

 Limenitis {s. I.) and their models, in Trans. Ent. Soc. Lond., 1908, 447-488. Dr. 

 Jordan's later conclusions as to the affinities of Danaida plexippiis, added to the 

 memoir in a terminal note (488) and somewhat at variance with his earlier con- 

 clusions quoted in the text, are here adopted throughout. A broader and less 

 detailed treatment is followed in this address, special attention being directed to 

 the numerous points on which further obser\-ations are required. Where no 

 other authority is mentioned, I have followed the synonymy and geographical 

 distribution of Scudder's great work, Butterflies of the Eastern United States and 

 Canada, and, for the Papilionidae, Rothschild and Jordan's fine monograph 

 {Nov. Zool., xiii, 1906, 411-752.) I have not, however, followed Scudder in the 

 general use of Basilarchia as a generic name, because I think that the whole 

 group of Limenitis, in its widest acceptation, requires revision, and that until 

 this has been accomplished it is inexpedient to adopt the terminology pro- 

 posed for a portion of it. 



