IX CEETAIN LEPIDOPTERA. 275 



perhaps indicated by its colour, which may be pale fawn, or rufous, or deep sienna- 

 brown, or even almost black, always with a polisbed surface. 



4. The Scaphium. 

 By this term I indicate a curious organ, which I find almost always present, of com- 

 plicate structure, apparently having an intimate relation to the uncus, and even, in 

 general, organically united with it, but yet occupying its proper place even in those rare 

 cases in which the uncus itself is obsolete, as in Orn. Brookeana, P. Podalirius, and 

 Bathycles. Indeed in this last-named it is seen to great advantage ; and still more so in 

 Mayo, the beautiful representative of Poly inn est or in the Andaman Isles ; and most of 

 all in the African Merope. 



The instant we have removed either of the valves from one of these Butterflies, our 

 attention is arrested by a great mass of shining white tissue, occupying the chief place in 

 the genital cavity, and projecting far into its area. We trace it up to an intimate and 

 apparently organic union with the lower surface of the uncus near its origin, far back in 

 the palate of the bird's skull (if I may use my own comparison on p. 274, supra), 

 whence it descends and dilates, sending large angular lobes back even into the abdomen 

 (Bathycles), but chiefly developed forward, like the contiguous organs. I have likened 

 this prominent part of the organ to a lower jaw (rather mammalian than avian , however) 

 — Machaon, Turtms, Erithonius, Bemoleus, Maceduu ; I have likened it also to a boat — 

 Mayo, Pammon. 



Of the function of this conspicuous organ I cannot speak with certainty. I adopt a 

 distinctive appellation for it (presuming it to be important and undescribed), which 

 leaves function untouched, and looks only at the accidental resemblance alluded to — 

 <TA.a*fn), (jKaty'iov, a boat. 



Where it is most perfectly developed, e. g. Mayo, the sides swell out like the bows of a 

 ship, while the mesial portion is abruptly thinned away to a deep projection, like a cut- 

 water and a keel. The upper surface forms two dilated margins (the gunwales of the 

 boat), with a deep sulcus between, in which in some cases — Vertumnus, Erechthens, 

 Bheleuor — the uncus lies. More usually there is considerable vertical space between 

 the uncus and the scaphium-margins. These very generally bear (here the simile shifts 

 back from the gunwales of a boat to a lower jaw) a compound armature, most difficult 

 to explain, but in which surely lies hid the key to the explanation. In some clear 

 examples it mimics the double molar tooth of a mammalian jaw, the outer usually much 

 more distinctly developed than the inner, often rising to a strong, conical, produced 

 spine, which may take the form of a straight blunt pin or peg — Memnon, Nireus ; or that 

 of a canine tooth, erect, acute, recurved — Mayo, Pammon, Arclurus, Macedon, Thoas ; 

 horizontal, recurved — Machaon, Ulysses ; horizontal, decurved — Bhodifer. Both may 

 appear as two equal, stout, polished cones — Momerus ; more commonly the secondary is 

 reduced to a mere conic knob, or is even obsolescent ; occasionally a third supernumeraLy 

 tooth or knob appears — Mayo, Rome r us ; and not infrequently neither can be detected, 

 e. g. O. Arruana. 



Besides these teeth, there is another kind of arming : the gunwale-like margin rises 



39* 



