HENRY SKINNER 195 



STUDIES IN THE GENUS THANAOS 



BY HENRY SKINNER, M.D., SC.D. 



These butterflies for many years have presented great difficulties 

 and have been stumbling blocks to students. In 1870, S. H. Scud- 

 der and Edward Burgess published a paper in the Proceedings of 

 the Boston Society of Natural History, entitled, "On the Asym- 

 metry in the Appendages of Hexapod Insects." In this paper they 

 described eleven new species from genitalia alone. It seems that 

 the remarkable asymmetry of the genital appendages was acciden- 

 tally discovered. Their remarks on the subject are of interest. 

 "In a recent study of the external genital organs of the males of 

 butterflies we.chanced to examine those of certain native species of 

 Nisoniades, and found not only a great difference between allied 

 species, but a most remarkable asymmetry between the opposite 

 clasps of the same individuals; this has led to an examination of all 

 the North American species of which we could obtain specimens 

 for dissection and the results are embodied in this paper." This 

 interesting and valuable essay has never received the study and 

 attention it so well deserved and the attitude of students toward 

 it has been somewhat peculiar. 



W. H. Edwards in his Catalogue of Diurnal Lepidoptera, pub- 

 lished in 1884 makes no mention of these species. In his Catalogue 

 of Diurnal Lepidoptera of America North of Mexico, published in 

 the Transactions of the American Entomological Society (1877) he 

 says, "The species credited to Scudder-Burgess, were character- 

 ized solely from peculiarities in the genital armor. I do not regard 

 such characterization as a " description' entitling a species to recog- 

 nition, and declined to admit these in the Synopsis. But in defer- 

 ence to Mr. Lintner's wishes I give them here as I would in excep- 

 tional cases give manuscript names. How valueless the genital 

 armor is for specific distinctions may be inferred from the syn- 

 onymy." His reference to the s>TionjTny means that he put 

 nearly all of the Scudder and Burgess species as sj^nonyms of 

 juvenalis Fabricius.^ Strecker (Rhop. et Het., p. 118) refers to 

 them as follows: "These separated from the old species and each 



1 In his 1884 Catalogue he says in regard to these names, "Described 

 solely from the genitalia and not recognizable." 



TRANS. AM. EXT. SOC, XL. "^^ 



