312 ME. P. H. GOSSE ON THE CLASPING-OEGANS 



Papilio Hesperus, Westw. (Plate XXX. figs. 21-24.) 



Valve of the outline of a Gothic arch obliquely cut off at base, wholly surrounded by 

 a dense and wide fringe of grey-brown hair-scales, densest and widest at and around the 

 tip. Interior surrounded by a wide flat shelf, within which the cavity abruptly descends, 

 and is deep. 



The harpe occupies the whole of this deep area, and fits it accurately with a chitinous 

 hollow plate of extreme delicacy and transparency, thickening and darkening all round 

 into a narrow edge, which stands up free, like a little wall, the summit rising into rounded 

 eminences here and there (PL XXX. fig. 21). The structure could not be detached in 

 integrity ; the ventral portion of the circuit is represented at fig. 22, viewed from the 

 ventral side. It is now seen that the free edge is cut into saw-teeth, and these by no 

 means simple, but elaborately compound, each tooth, at least for a considerable portion 

 of the edge, being itself cut into three, or even four toothlets, and each of these com- 

 pound teeth being the termination of a rounded curved ridge on the outer surface of the 

 wall. I have found no structure elsewhere quite analogous to this. Fig. 23 represents 

 some of the teeth on a more enlarged scale. 



The abdominal apparatus is of the ordinary type ; the uncus is moderately long, in- 

 clining downwards, nearly straight, crowned with a ridge of stiff erect hairs, deeply 

 keeled. Scaphium moderate, double teeth strongly developed, erect, incurved, acute. 

 Penis doubly curved, finger-pointed, moderately thick, and so long as to project hori- 

 zontally between the valves when these are closed. 



Papixio Demoleus, Linn. (Plate XXX. figs. 25-27.) 



Valve-outline an oblique semiovoid ; exteriorly clad with a coat of drab-white, short 

 scales, which project in a very slight fringe just around the extremity. Interiorly the 

 surface smooth, but not shining ; the cavity rather narrow, running to a point, bounded 

 by a broad flat shelf on each side, of which the dorsal extends only half down, the ventral 

 the whole length. ; 



Harpe a broad thin plate of yellow transparent chitine, not very concave, reaching to 

 within two thirds of the valve's length ; its ventral edge an elevated ridge, apparently 

 tubular, with an expanded base ; the ridge, like a clear glass tube, is marked, at short 

 intervals, by ten or twelve distinct black transverse lines, suggesting joints, or rings of 

 metal binding a pipe for increased strength. Close to, but not quite at, the extremity 

 of this ridge, which diminishes to a thin scalpel-like edge, there is a single minute black 

 tooth projecting obliquely towards the dorsal side, the upper edge of which, in the 

 specimen examined, showed a few minute notches, possibly accidental. The area of the 

 harpe is corrugated into fine ramifying wrinkles, and studded with very minute circular 

 areola? (pits ?), from each of which springs a hair, varying in fineness. The lining-mem- 

 brane of the valve is similarly studded, the areolae and hairs specially crowded toward 

 the point. The fringing hairs (hair-scales) are in the same plane as the valve-surface ; 

 these perpendicular to it. Besides these hairs, there lie, about the area of the harpe, 

 many body-scales, of varying forms, which, derived doubtless from the other sex, usefully 

 illustrate the function of this organ. 



