282 ME. P. H. GOSSE ON THE CLASPING-OKGANS 



10. The points produced, into long styles. 



Archesilaus. Zalmoxis. 



11. The plate complicate, sending off many laminaa and points, often serrate. 



Policones. Agesilaus. Codras. 



Ucalegon. Parmatus. 



12. Rotundo-triangular, with a spoon-like knob, usually studded with points. 



Nireus. Polydorus. Hector. 



Dipliilus. Antenor. 



Specific descriptions. 



Ornithoptera arruana, Feld. (Plate XXVI. figs. 1-3.) 



In this grand butterfly the valve is of unusual size, measuring "3 inch in length, and 

 "33 in breadth. Externally it is uniformly brilliant yellow ; internally, rich velvety 

 brown. Its outline is rotundo-triangular, with the dorsal side cut off obliquely at the hasal 

 moiety, and the ventral side correspondingly produced. The ventral margin is broad 

 and flat, or rather slightly channelled ; there is a projecting blunt tooth, about one third 

 down this margin ; and the whole is surrounded by a narrow fringe of hairs, blackish 

 and dull on the dorsal, brassy and glittering on the ventral edge. The ventral margin 

 forms a wide flat shelf throughout, before the level descends to the concavity. 



At the very base of the valve begins an ample Iwrpe, in the form of a broad plate of 

 glittering chitine, narrowed slightly in the upper part, and then expanding into a spoon- 

 like disk, of which the terminal edge is flat, oblique, and beset with minute black 

 glittering, curved, acute spines, the points directed ventrally, arranged, inexactly, in 

 transverse rows, of which there are about seven on the dorsal edge, diminishing to one 

 before the ventral angle is quite reached *. 



The hurpe consists of two surfaces, as if a tube had been flattened ; and, besides this, 

 the upper surface is hollowed both immediately below the spincd disk, and in the basal 

 moiety. The terminal portion, about one fourth of the whole, is disconnected with the 

 lining membrane of the valve, to which the remaining portion adheres ; but the whole 

 can be lifted, and separated from the valve by delicate manipulation, and placed on a 

 glass slide for higher amplification. The component chitine is now seen to be quite 

 transparent, of a rich yellow-brown colour, deeper at the edges, and specially at the 

 extremity, where the spines are glittering deep black. All over the body of the harpe 

 ramify many irregularly sinuous lines, like rivers in a map ; and these, I found, by an 

 accidental fracture of the structure, are not on the outside, but on the inside of the walls. 

 When the valves are closed, the pah' of spinous disks meet accurately at the very tip of 

 the uncus, as may be seem with the left valve in PI. XXVI. fig. 3. 



The uncus is a wire of extreme slenderncss, black, polished, very slightly curved, 

 ending in a point, not sensibly dilated, not very acute ; the basal portion of the upper 

 surface bears a ridge of close, stiff, black hairs, which stand nearly upright. 



* It must be remembered that, as in many otber eases, this is the careful description of an individual ; the 

 minuter features may not be repeated in every example. 



