( 498) 



pecuniary sacrifice, the student of the variation of an internal organ, wiiicli is not 

 visible without dissection, is at a great disadvantage compared with the student of 

 external characters, because his series of individuals is always taken at random ; he 

 has no secnrity wliatever that, among the hundreds of specimens whicli perhaps 

 are at his disposal, there are really individuals which in the genital armature 

 represent the extremes of that species, or come near the extremes ; while, on the 

 other hand, the specimens conspicuously aberrant in wing-pattern, or colour, or 

 shape, are recognised and preserved by collectors, which gradually results in an 

 accumulation of individuals which fairly rei>resent the various degrees, inclusive of 

 the more extreme ones, of the variation of the species in external characters. 

 Hence it is by no means to be wondered at that there are so many individuals 

 known which in external characters stand far outside the ri.'oifil limits of variation 

 of the respective species, while the internal genital armature seemed to vary only 

 within very narrow limits. On the contrary, it must surprise us that we neverthe- 

 less did succeed in finding among our specimens such individuals as exhibit in the 

 genital organs characters so widely divergent from the normal of the respective race 

 of Pfipilio that the individual not only ibrtns a transition to another geographical 

 representative, but goes in the development of the peculiar character even beyond 

 allied forms. The specimen of P. sarpedon sarpedon (f. 101, 102, 103) and those 

 of P. (dcinous figured on PI. VI. of Vol. II. of this journal (f 1 1 and 1 3) are such 

 " unusual " varieties, which perhaps are in nature not rarer than individuals that 

 in external characters come close to, or are identical with, one of the allied forms; 

 and we have no doubt that a continued investigation in the matter will bring to light 

 varieties in the genital armature which in the degree of divergency are equal to so- 

 called sports. The individual variability found in onr series of British P. machaon to 

 amount to 40 per cent, in the gradual increase of the length of the prehensile portion 

 of the harpe, and in Palaearctic machaon to 70 per cent., is quantitatively scarcely 

 inferior to the variation exhibited in external characters, and the same applies to the 

 other Papilios dealt with in the preceding chapter. In the female genital armature 

 we meet with an equally great variiibility in many of the species, especially in all 

 those which have a more complicated armature ; the variability of the complicated 

 apparatus, which consists of spines, hooks, dentate ridges, and so on, appears 

 generally to be greater than that of a simpler armature, because the diflFerence 

 i)etween the apparatus of two individuals is more easily perceivable in a com- 

 plicated than in a simple organ, even if tlie dilference in the latter expressed in 

 proportional numbers is greater than in the former. 



If we group the individuals of a species from one locality according to the 

 similarity in the genital armature, and then again according to a conspicuous 

 external character, the first series of groujis and the second are not the same ; we 

 have found again and again that specimens similar in a certain character in colour, 

 pattern, or shape of wings have no particularity in the genital armature in common 

 by which they are distinguished from the individuals that do not possess that 

 external character; specimens aberrant in wing-iiattcrn may be normal in the 

 genital armature, and individuals abnormal in the latter may be normal in the 

 former. The harpe of /-". aegeus ormenua with a band on the forewing is the same 

 as in the aberration without the band; P. cuchenov i-xrlienov ab. eutropius does not 

 differ in the harjie from the ordinary male ; /'. poli/tes horealis ab. ikihet'inufi has a 

 normal harpe, and so on. Still more obvious is the independence of the variation of 

 the genital armature in the species with polymorphic females ; the various females 



