( 499 ) 



have something characteristical in these organs — a fact which is not difficult to 

 ascertain bj- comparison with those allied species which have been proved to be 

 distinct by their life-liistory. lu the case of Precis there were the Vanessa and 

 the seasonally dimorphic Araschnia, which could have served as gaides. We said 

 in 1896*: "... Most probably the artificially produced colour-varieties will be 

 normal in the genital armature. To this conclusion we are led by the experience 

 gained from the e.Kamination of seasonally dimorphic species. We paid special 

 attention to the copulatory apparatus of such species, with the hope of finding in 

 one or the other Papiiio differences in the apparatus of the spring and summer 

 brood (or broods), but completely failed to come across a species which, both in the 

 wing-markings and in the sexual organs, showed seasonal dimorphism. ... In 

 the case of winter and summer forms it is therefore evident that the influences 

 which bring about a change in the wings have no apparent effect on the sexual 

 armature." . . . [p. 502] " If we apply this conclusion to the species of Papiiio 

 externally jmlymorphic, it is evident that the genital armature of male and female 

 is an excellent criterion of specific identity. The various varieties of the male of 

 P. aeqeus ormenus from New Guinea, of Troides priamus poseidoii from the same 

 country, of P. memiion, and so on, many of which have been described as new 

 species, are thus easily demonstrated to be specifically the same. Still more 

 important is the application to the female sex. The nnmerons species with 

 polymorphic ymafes, which so often are quite unlike each other, as in the case 

 of P. memnon, P. aegern ormenus, P. polytes, and the African P. phorcas and 



meroue, and some American species an examination of the genital apparatus 



of a number of specimens will at once make it clear whether the forms in (piestion 

 belong certainly to one sijecies, or whether they eventually can belong to more 

 species." 



Since then we have kept this subject in view during all onr researches, and 

 have in various places drawn attention to the fact that seasonal and individual 

 dimorphism is not accompanied by diifercnces in the sexual armature, while 

 geographical varieties are in numerous cases distinguished by a more or less 

 obvious peculiarity in the copulatory organs. We do not think that systematists 

 who examine these structures will very often be deceived by polymorphism. On 

 the contrary, the danger for them lies just in the opposite direction. They will 

 be inclined to regard as varietal members of one species all those forms which do 

 not exhibit distinctions in those organs. However, they will be wary if they know, 

 as we know now, that there are many distinct species wliich are identical in the 

 coi)ulatory armature. The systematist need not stop at the examination of those 

 structures. What prevents him from improving his methods of research in 

 accordance with modern requirements, just as the methods in other branches of 

 zoology have been improved ? If the Lepidopterist caimot come to a satisfactory 

 conclusion from the examination of the pattern, colonr and sha]te of the wings, the 

 neuration, the structure of the legs, mouth-parts, sexual armature, etc., he must 

 learn to extend his research still further. The dry cabinet-specimens of insects do 

 not present the comiiletc organisiition of the live individuals. But the Entomologist 

 is at least in a better position than the stuih'nt of iiird- and mammal-skins, his 

 specimens being more com])lete. He is even able to anticii)ate the observations on 

 the early stages to a certain extent. The eggs are always at his disposal in the 

 body of the y'e//jaif««— lack of material, of course, puts a stop to all research, as does 



• Mechanical Srlrctiim p. iW; in Nov. ZOOL. iii. 



