336 ME. P. H. GOSSE ON THE CLASPING-ORGANS 



provocant organ, to be applied to the ? vagina, before intromission ? The extreme 

 tip seems to be of peculiar structure : it may be glandular, and bo the seat of sensation, 

 the reW-c epvriKv, of wbich the hard chitine of the penis seems incapable. 



In one example the whole keel was movable, as on a hinge in the interior, whose 

 place is indicated by the dotted curve-line in fig. 15. 



The thickened edges unite behind into a very thin median ridge, which, like a groin 

 from a roof, descends vertically, and is lost in the curtain to be presently described. A 

 transverse horizontal section would be somewhat like fig. 19. 



In O Remus, and, I believe, in Ornithoptera generally, the uncus is soldered by its 

 under surface to the upper surface of the scaphium-cheeks behind, the suture showing a 

 thickened bead. So it is with some Papilionides, though with others there is a wide 

 hiatus between these organs to the very base. That the fecal outlet perforates the 

 abdomen-wall at their point of union seems certain. In both Remus and Ralvphron I 

 have demonstrated the presence of an orifice, leading from the abdominal cavity between 

 the uncus and the scaphium, and I have passed a fine needle through it-though, from 

 the extreme minuteness of the parts, and their dry condition, the demonstration was not 

 quite so satisfactory as I could wish. Still I can find no anal orifice possible anywhere 



else than here. . , 



The tissues of the scaphium become attenuated and expanded bebiud, arching around 

 as a great concave membrane (fig. 15), which limits the genital cavity, and shuts it off 

 from the abdomen as by a falling curtain. It is strengthened by slender ribs of chitine, , 

 which run down vertically from the cheeks of the scaphium and from the groin of the 

 keel, somewhat like the nervures in the membrane of the wings, and end in insensible 



points, near the penis. 



Penis M\ my examinations still leave much obscurity on the form and conditions ofl 

 the intromittent organ. Its usual appearance is that of a semitube, or gutter, of brown 

 chitine whose upper (normally and structurally the lower or ventral, for the organ is 

 reversed) side is widely open, which projects from the curtain outward to near the tip 

 of the scaphium-keel. But these gaping sides approach each other in various degrees in j 

 various individuals, the organ at times being nearly flat, especially towards the extremity. 

 It is then seen to have angular enlargements at intervals, which, when the sides approxi- 

 mate appear as sharp projecting ribs. The tip is bevelled off to an acute or subacute point, 

 Lm Ih side of which a ridge passes down into the hollow (fig. 20). [These characters 

 were precisely repeated in examples of O. Uahj.hron^ 



But I have seen specimens in which the trough was more than filled with a substance : 

 which though it was not white, 1 suspect to have been homologous with that pulpy 

 matter which I have repeatedly described-the more, since in this case too a portion of: 

 it was extruded to some distance from the extremity. 



It is difficult to imagine how an open trough can be efficient for the conveyance oft 

 the semen into the S vagina. But I venture to suggest though I have no proof, that 

 in life the tube may be completed by an excessively subtle film, which, in drying, falls 

 on the opposite chitine-surface, so as to be no longer distinguishable. 



