ZOOLOaY AND BOTANY, MICROSCOPY. ETC. 649 



and these and other ridges are usually more or less beset with hooks 

 or points. The form of the organs varies immensely, e. g. from that 

 of claws, hooks, pikes, and swords, to mere knobs or combinations of 

 these. The base is always expanded and disk-like. The muscles 

 which work them are probably attached to two short, thick, chitinous 

 processes placed at the bottom of the abdominal cavity. The func- 

 tion is certainly to grasp the female during impregnation, the teeth 

 being frequently found clogged with scales. 3. Uncus (tegumen, 

 Buchanan White). This name is applied to the hinder margin of the 

 8th abdominal segment, which is drawn out into a point in Ornitho- 

 ptera and Papilio ; and this point is usually armed with a strong horny 

 spine. The form of the point varies much, being spoon-like in Papilio 

 Bhodifer, bifid in P. Agamemnon, trifid in others, curved upwards 

 in Agamemnon, downwards in other species, short and thick in 

 P. Antenor, &c., slender and bowed in Ornithoptera Arriiana, &c. ; the 

 margins are turned strongly up in P. Macliaon, &c. The dorsal sur- 

 face of the segment may be marked with depressions, or may have a 

 median ridge of long hairs which project horizontally, so as to cover 

 the generative cavity (P. Agamemnon, &c.), or the hairs are erect 

 (P. Ei-echtJieus, &c.). The uncus is absent in P. Hector and Poda- 

 lirius. To the annular part of the 8 th segment Mr. Gosse confines 

 Buchanan White's term, tegumen. When the valves are fully deve- 

 loped, the uncus lies directly below the line of their dorsal point of 

 opposition ; from its lower surface two laminas usually extend down- 

 wards, commencing near the point. The uncus combines with the 

 harpes to grasp the female's abdomen. 4. ScapMum (lateral plates ? 

 De Haan) originates from the lower surface of the uncus near its 

 base, whence it descends, dilating, and sends angular lobes back 

 towards the abdomen. In Papilio Machaon and others the distal part 

 resembles a mammalian lower jaw, in P. Mayo and Pammon a boat, 

 a median cutwater and keel being readily distinguishable from the 

 bulging sides in P. Mayo. In any case, the upper surface has two 

 dilated margins, between which the uncus sometimes lies ; these 

 margins bear teeth resembling the mammalian double molar, the 

 outer cusps being usually the larger, and having the form of a blunt 

 peg, or a canine tooth, or one horizontal and recurvate or decurvate ; 

 or the two sets may form two equal, smooth cones ; a third part is 

 occasionally present ; both are absent in Ornithoptera Arruana. In 

 P. Merope the stout broad teeth are especially richly beset with notches 

 and bristles. The double teeth are sometimes replaced {Ornithoptera 

 spp.), occasionally accompanied {Papilio Erectheus) by a sharp ridge, 

 cut into parallel erect teeth, by which the margins of the scaphium 

 are produced upwards. The connections of the lower part of the 

 scaphium are obscure, but its descending rami sometimes embrace, 

 though they are apparently not in organic connection with the penis. 

 It is usually opaque white, smooth and shining, and then must be 

 mainly muscular, probably working not only its own teeth, but also 

 the uncus, and perhaps in part the valves and harpes also; but in 

 P. Podalirius, &c., it is more or less brown, and contains chitin. 

 5. The Pern's, though not " auxiliary," is fully treated of, and its varia- 



