310 MR. P. II. GOSSE OX THE CLASPING-OBGANS 



parency, which occupies the central area of the valve. Each wiry edge is armed with a 

 prehensor ; the ventral edge, a little beyond its middle, bears a long acute spine, which 

 stands up from it, and curves obliquely forwards ; the dorsal, a thicker cone, more erect 

 on its base, which first sends off a nearly straight horizontal spine obliquely forwards, and 

 then terminates in a shorter and blunter point. 



The uncus arches in a regular semicircular curve to a small spathulate point ; a deep 

 keel beneath the receding rami ; between which issues the moderately large scaphium, 

 well keeled, the only peculiarity noticed being that the extremity of the keel, by its 

 deepening hue, appears to become more chitinous, until it ends in a minute horny 

 point. The double teeth are minute, but distinct, conical points. 



The penis is small and high-situate. 



Papilio Polvcaox, Cram. (Plate XXX. figs. 10-19.) 



T'a Ice-outline subrhomboidal, with rounded angles, thickly fringed on the dorsal 

 (short) side, but thinly on other parts. 



Harpe a broad, concave plate of thin, clear, shining chitine, beset with fine, short 

 bristles, pointing outward, as is also the lining-membrane where it is exposed. The ven- 

 tral edge of this plate is a slender nearly straight rod, polished, black, with a fine-drawn 

 acute point, free for some distance. The upper edge of the thin plate usually springs 

 from the spine a short distance down, and rises into a wide curve ; sometimes it follows the 

 spine up to its point, and descends at an acute angle ; but presently, on what I may call its 

 dorsal corner, it gives rise to a curious appendage, which usually takes the form of a thick, 

 short, solid column of black chitine, set, all round its summit, with stiff tooth-like spines 

 (fig. 18) ; but sometimes appears as a smaller knob, with a slender base, whence rise three 

 diverging lamina?, united by their inner, and serrate on their outer edges (fig. 17). In 

 either form, the spines are of a clear, glassy, blue-black substance, and most of them are 

 double, *. c. each has two points from the same base. The spinous rod of the ventral edge 

 bears a triangular thin elevation (and sometimes a secondary one) near the base. 



The uncus is long, slender, evenly curved, acute; the keel of its united vertical rami 

 deep, and diminishing in depth gradually to the tip. 



The scaphium is very ample in all its constituent parts ; the cheeks rise into high 

 arching crests, with notched, aristate edges, but destitute of double teeth, so far as I can 

 discern ; the sides run down on either hand in great oblique folds ; the keel is pointed, 

 large, and deep; all the parts are shining white. The penis presented no features 

 worthy of special notice, other than can be observed in the figures. 



In my cabinet are examples of six very diverse kinds of butterflies, all large, imposing, 

 and richly coloured, labelled thus : — Androgens, Cram., 6 and 2 , from Brazil ; Thersiles, 

 Pabr., 6 and 2 , from Jamaica ; Polycaon, Cram., 6 , and Lyeophron, Hiibn., 2 , from 

 Corrientes, in the Argentine Republic *. 



* Those may be readily distinguished thus: — Males: 1, hind wings with no yellow hmules= Androgeos ; 2, with 

 shallow yellow kmvles=Thersites; 3, with deep yellow lumiles= Polycaon. Females: 1, fore wings with a broad 

 straight yellow bar across =Andror/eos : 2, with a narrow curved yellow band across =Thersites; 3, no yellow band 

 across = Lyeophron, i.e. Polycaon $ . I describe from my own specimens, which differ from Cramer's figures. But 

 what I call Polycaon may possibly be the Oebalus of Boisduval (Sp. Gen. p. 3G0), with whose description they fairly 

 agree, except that I see no trace of the " red-brown lunules " that he assigns to the hind wings above. 



