( 504 ) 



But within the group a species could very well be noarly ivlated to another in the 

 pattern of the wing, while it comes in the structure of the co])ulatory organs of the 

 male ov female closer to a third species, so that the relationship of the sjoecies inter se 

 would appear to be different according as we take as the standard of arrangement 

 the deviation in the one or the other organ. 



If, however, it is true that the species which belong to the same group (of 

 allied sjiecies) are in the genital armature more similar to one another than to the 

 species of other groups, we have consequently to conclude that the organs of copula- 

 tion are a safe guide to determine to which group a species belongs, which means 

 that these organs can be made use of in generic classification. The great helj) which 

 the genital armature affords to the systematist is beautifully illustrated by those 

 species which bear to each other a superficial resemblance in pattern, such as 

 F. clytia and leucotKo'c or macaietis, P. i-hesus and jjliilolaus, which on the ground of 

 the alleged relationship in pattern have been considered allied species. Though a 

 careful examination of the wing-markings soon convinces ns that we have here and 

 in many other Fapilios to do with au analogous develojjmeut in pattern, as in the 

 case of mimetic forms, which does not indicate blood-relationship, the demonstration 

 of the dissimilarity in the morphology of the organs of copulation of those super- 

 ficially simOar species will be a more convincing guide in which direction the actual 

 relationship is to be sought for. 



Having thus arrived at the two conclusions, firstly, that identity in the sexual 

 armature means specific identity, and secondly, that close relationship in these 

 organs points to generic identity, the question arises, whether there are in the 

 organs of coi)ulation of specifically distinct Papilios, as opposed to specifically non- 

 distinct forms, characters which a priori could be recognised as being of specific 

 value, and hence would enable us to draw up a general rule applying to every case 

 by which specifically distinct forms could be distinguished from specifically identical 

 forms. The occurrence of individual and geographical variation in the ('opidatory 

 organs, the latter kind of variation always associated with an independent variation 

 in the wing-markings, renders it alone highly improbable that a general distinction 

 between specific and subspecific characters is possible. A comparison, however, of 

 the degree of divergency between subspecies with the degree of divergency between 

 closely allied species proves that the quantilative amount of divergency between 

 specifically identical forms can be superior to the quantitative amount of divergency 

 between allied species. 1'. itiopiimtus differs in the harpe (f. 12) not so much 

 from certain examples of F. aegetis as some of the latter do from one another 

 (f. 4, 5) ; the difference between the harpe of P. poli/tfs pohjtes (f. 18) and 

 F. polytes alphenor (f. 33) is greater than that between F. polytes and F. amhrax 

 (f. 35, 37) ; the difference between F. aristeus parmatm and P. aristeiis anticrates 

 in the harpes (f. 73, 75, 81, 83) is not inferior to the difference between F. aristeus 

 anticrates and F. rhesvs, which latter is considered to be a species distinct from 

 aristeus (f. 82, 84). If, however, there are such cases like these in which that 

 difference which is the greater in quantity is the smaller in quality (in respect to . 

 specific distinctness or non-distinctness), it conseiiuently follows that it is impossible 

 to say a priori which degree of quantitative divergence in the organs of copulation 

 is in all Papilios of specific value. Hence a peculiarity observed in the sexual 

 armature of an individual can be au aberrational, a subspecific, or a specific 

 peculiarity; which of the three it actually is, we can learn only from a careful 

 weighing of all the evidence. \Ve liuve said in the introduction that the evidence 



