168 PROCEEDINGS OF THE ACADEMY OF [Jan., 



obvious that this interpretation of the resemblances borne by other 

 insects to the stinging Hymenoptera cannot be thus explained, 

 and, within the Lepidoptera themselves, the study of detail has 

 often furnished a refutation. Thus Prof. Gowland Hopkins (13, 

 p. 68i)) writes: "The mimicking Pierid retains the characteristic 

 pigments of its group, while those of the mimicked Heliconid are 

 quite distinct. This would seem wholly to refute the argument 

 that in such cases the likeness may spring from a real affinity between 

 the two insects." (See p. 176.) 



5. Sexual Dimorphism (Antigeny of Scudder) and Mimicry. 



The mimetic butterflies of North America, as in other parts of the 

 world, are in large part mimetic in the female sex only, forming a 

 special subsection of the far wider group of sexually dimorphic or 

 antigenetic species. Dr. Skinner seeks to explain the special sub- 

 section and the inclusive group by an appeal to the same general 

 law. Thus, speaking of the mimetic females of North American 

 Papilios, he says on p. 125: "These differences [between the sexes] 

 occur in numerous species and it seems logical to consider that they 

 are governed by a general law rather than that a few of them are 

 caused by protective resemblance." He uses the same argument 

 concerning the female Argynnis diana, which Scudder maintains in 

 the most positive terms to be a mimic of Limenitis (B) astyanax. 

 (6, 1, pp. 266, 287, 718; III, p. 1802). Comparing this Argynnid with 

 five other sexually dimorphic species of the genus in North America, 

 Skinner says on p. 126: " It does not seem consistent to pick out one 

 species (diana) and say that its antigeny is due to tertiary mimicry. 

 How can the dimorphism of the other species be explained?" But 

 the female diana is, according to two eminent North American 

 entomologists, Scudder and Edwards, picked out by nature and 

 distinguished among the other antigenetic females by the fact that 

 it resembles a species of a very different Nymphaline genus. I agree 

 with them — although my opinion is worth very little as compared 

 with theirs, for I have never seen the species alive — and I was seeking 

 to place a resemblance which puzzled Scudder, in its true position 

 among the mimetic butterflies of the Region. The far wider ques- 

 tion of sexual dimorphism in general did not fall within the scope of 

 my paper. Again, referring to the mimetic female Papilio, I do not 

 know why it is specially logical to seek to explain by the same general 

 law two very different categories, viz., the sexually dimorphic 

 females that closely resemble other species and those that bear no 



