268 ME. P. II. GOSSE ON THE CLASPING-OEGANS 



It might seem that, by the aid of organs so uniformly present, so easily examined, and 

 so varied in different species, while constant in the same, great facilities must he 

 afforded for the determination of specific identity and limitation. Yet, in practice, I fear 

 this cannot he carried out, without severing species which otherwise seem most closely 

 allied, and linking others which have little else in common. Look, for instance, at the 

 three African species Papilio Promhts, P. Nireus, and P. Pkorcas; how consimilar are 

 these in their forms, colours, and markings ! yet how diverse in their whole prehensile 

 apparatus ! The shape of the valve, its fringing ; the shape of the harpe, its armature ; 

 the uncus ; the teeth of the scaphium ; and, finally, the penis ; — all these differ signally 

 in one from their conditions in the others, as may he seen, at a glance, from the following 

 pages. The like terms might he employed concerning P. Demoleus and P. Erithonius. 



It needs scarcely to he told that all the following observations were made on dried 

 specimens. The desiccation of the soft tissues, causing them to shrink, throws into 

 distinct prominence the hard chitinous organs with which these pages have mainly to 

 do ; and their form is not affected by drying. Indeed, the density and unyielding hard- 

 ness of this material are manifest by the depth of colour it can assume, often approaching 

 to black, by its brilliant polish of surface, by its transparency like that of glass, and 

 by the delicacy with which it is fashioned into the thinnest edges and cut into the 

 sharpest teeth, which, strange to say, we never see blunted by use. 



Let it be remembered that, while a considerable number of the following descriptions 

 and figures have been confirmed by observations repeated upon two, three, or even more 

 successive examples, many (somewhat more than half) rest upon individuals. These, 

 though made with all care, are like the «?rn^ Xeyofieva of the critics, and must be accepted 

 with a certain measure of caution. 



Manipulation. 



My methods of manipulation are of the simplest. With a penknife, worn by age to a 

 very fine and keen point, I make incisions, vertically as the insect lies on its side before 

 me, along the hinge-line of one valve (I have usually selected the right) : presently, using, 

 with a gentle violence, such a lever as the tip of a toothpick, the valve is prized off. By 

 practice, I am able to do this with very little chance of injury to the specimen ; and when 

 my examination is completed, I restore the valve to its place, with the minutest touch of 

 gum-tragacanth ; so that, when it is dry, and the butterfly returned to the cabinet, I am 

 often quite unable, some lime after, even myself to determine, with certainly, of two or 

 three examples in the drawer, which it was that I had nsed for the operation*. 



The detached valve is then submitted to strict search with the various powers of a 

 triple lens, reaching in combination to 24 diam. When the information deducible from ' 

 this aspect seems exhausted, if the harpe appear to promise any more, I essay to lift it 



* The circumstance thai the exotic Papiliones are often of high monetary value has no doubt much impeded omj 

 acquaintance with their anatomy. Our museums and private collections are rich in species; hut few possessors are 

 willing to submit their treasured beauties to the anatomist's scalpel. Perhaps Prof. Siebold's sarcasm is not yet 

 wholly without force : — "Mosi collectors seem ambitious only to keep their butterflies neat and untouched, or to 

 gain thereby advantages other than scientific" (--On the :, of Parn. Apollo" Stett. Ent. Zeit.. 185] |. 



