



MIMICRY IN BOREAL AMERICAN RHOPALOCERA 



By Henry Skinner, M.D., Sc.D. 



Professor E. B. Poulton (4), the eminent student of the subject of mimicry, 

 states that the butterfly fauna of North America probably affords the best field 

 in which to take up this study. He also says the examples are sharp and striking 

 and not too numerous. He considers these problems to possess the most profound 

 significance in relation to the deepest questions by which the naturalist is con- 

 fronted. 



The literature of the subject has grown to large proportions and the subject 

 has engaged the attention of many observers. Some of our American species of 

 butterflies will be discussed in this paper from the standpoint of Batesian mimicry 



as defined by Poulton. 



This 



"is an advantageous deceptive resemblance borne 



by palatable or harmless species (the mimics) to others that are unpalatable or 

 otherwise specially defended (the models)." Some of the species in the genus 

 Papilio are said to be protected by their resemblance to certain other species in 

 the same genus which in the larval condition feed on poisonous plants. Following 

 Haase (8), Poulton has adopted the name Pharmacophagus for the so-called 

 poisonous models. 



Rothschild and Jordan (5) have divided the genus Papilio into three groups, 

 called Aristolochia-swallowtails, Kite-swallowtails, and Fluted-s wallow tails. In 

 the Boreal American fauna there are three species belonging to the first group : 

 polydamas, devilliers, and philenor. Polydamas is a West Indian species which 

 has been recorded from the Indian river, Florida. Devilliers is a Cuban species 

 that has also been taken at the lower extremity of Florida. Philenor is well dis- 

 tributed over the United States, except in the central district, from Colorado 

 northward. 



Two species belong to the second group: marcellus (ajax), and marcellinus 



(sinori) . 



The remainder of our species in the genus fall among the fluted- 



swallowtails. Three species are said to be protected by mimicking philenor ac- 

 cording to Poulton; they are Papilio polyxenes asterius, P. troilus, and P. glaucus 

 (the dimorphic black female) . 



To logically prove this assumption it is necessary to show that birds are in 

 the habit of eating butterflies and that some butterflies are poisonous or nauseous 

 to them and others not. The deduction that certain species mimic others, ac- 

 cording to the Batesian definition, would be difficult of proof, even if it be shown 

 that the first two propositions are correct. Guy A. K. Marshall (3) in an inter- 

 esting article entitled "Birds as a Factor in the Production of Mimetic Resem- 

 blances among Butterflies' ' gives a list of records for the Nearctic region and 





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