"Abdomen elongate, stout, the last segment always 

 furnished in the <? <? with 2 very large valves" | " These," 

 Wallace tells us, " are very large, ovate (or semi-ovate), 

 coriaceous (or leathery), and not hairy;" and, as 

 Gosse points out, externally convex, internally concave ; 

 in some species, such as Arruana, being densely fringed 

 with hair scales ; but he considers that (for reasons I 

 shall give in another section of this work) Ornithoptera 

 is a good genus. The anal termination of the 2 is 

 generally a dense tuft of hair scales, varying much in 

 the^ different species, and even individuals. These 

 entirely hide the vulva, or act as a dense fringe when it is 

 permitted to be visible, and extend entirely up the suture 

 beneath to the next segment of the abdomen. They are 

 generally darker, or, more ochreous in colour than in the 

 other abdominal parts.] 



_ " Larva tuberculate ; the tentacula contained in a fixed 

 bifid sheath. 



" Pupa stout, slightly arched, tuberculate ; head bifid." 



" In the larva state they differ from Papilio in having 

 an external forked sheath for the prothoracic tentacula. 

 The perfect insects have the prothorax more developed ; 

 the abdomen larger, longer and very deeply grooved 

 below; and the valves of the last segment far larger 

 than in any species of Papilio. The larvae resemble those 

 of some Thais and Papillons in being tuberculated. The 

 Pupa not surrounded by a transverse band, but sustained 

 by a silken thread on each side, attached to a small 

 lateral tubercle [Boisd. sp. Gen. i. 173] . Wallace 

 remarks in reference to this, that his own observations on 

 O. Poseidon show that the larva has no " external sheath " 

 to the thoracic tentacles, and that the suspending thread 

 passes round the pupa, and is not " fastened on each side 

 to a silky tubercle." Drawings of these will be given in 

 their proper place. 



To the foregoing the following facts may be added : — 



1st. The baseo-median nervule connecting the median 

 and submedian nervures of upper wing, makes its appear- 

 ance in an earlier family of the Diurnea, the Morphos, 

 where in the Genus Morpho it may be found, almost 

 hidden by scales ; and that portion of it which joins the 

 median nervure is bifid, each point united to the nervure 

 by a swollen fraction of the membrane of the wing, the 

 form of the whole being somewhat Y shaped. In Caligo 

 it appears to be absent, the corresponding part of the 

 submedian nervure curving up close to the median instead. 

 I find no trace of such characters in other families of the 

 Diurnea, though this is no evidence that they do not exist. 



2nd. The Precostal nervure is bifid in Ornithoptera, 

 and is found nearly of the same shape and bifid in the 

 Genus Caligo, but not in Morpho. It does not appear in 

 the sub-family Pierincs. 



3rd. The spur on the middle of anterior tibia? of front 

 legs is stout and of equal width 3-4ths of its length, the 

 remaining 4th being very sharply pointed. This spur is 

 hollow. It exists in the $ and 2 of all the sub-family 

 Papilionince. It can also be found more or less obscurely 

 present in the Hesperiidce, of which in one species, Ismene 

 jupiter, Fab., it is very prominent, and extends to nearly the 

 whole length of the tibia. It can be traced among the 

 Heterocerous Lepidoptera in Castnia, Urania,the Sphingidce, 



and even in Arctia. Possibly it may be found in the 

 majority of the lepidoptera, though often very rudimentary. 

 In some a pair of very fine spurs take the place of the 

 single one. These appear to be generally larger than 

 their congener in Papilio. 



4th. The great distinguishing superficial character of 

 the Ornithoptera is really the singular sericeous patch on 

 the Primary Wings of the <? . This is only seen on the 

 upper-side, and is a long pupaeform mark, covered with 

 scales of a different colour and character from those of 

 the rest of the wing, extending from the 1st median ner- 

 vule almost to the sub-median, and in width generally 

 occupying about 2-5ths of the space between the median 

 nervure and the Posterior margin of the wing. The 

 shape of the patch slightly differs in each species, and 

 indeed in the different specimens of the same species : a 

 significant fact, as we shall see hereafter. This patch 

 only appears in the Priamus group, that is to say, in the 

 typical Ornitlioptera and my section Priamoptera. Its 

 effect is to bend or distort the 1st, 2nd, and 3rd median 

 nervules midway : the first bending downwards, the 

 other two upwards, this arrangement being constant in all 

 the species. A slightly resembling character may be 

 found in a similar position in some of the Papilios, notably 

 P. Ulyssis ; but it is absent in the subgenera Pompeoptera, 

 Trogonoptera, and Aztheoptera, which I propose for the other 

 groups of the genus, being replaced in two of them 

 by an analogous character in the abdominal folds of the 

 Posterior wings. In Caligo automedon, Cram., and 

 C. cesacus, Herr Schaff, an analogous elongate -ovate 

 patch is situated close to the submedian nervure, occupy- 

 ing half the space between it and the 3rd median nervule 

 close on the edge of the abdominal fold, its length being 

 nearly i-5th of the length of the wing in a?sacus, i-yth 

 nearly in automedon, and i-4th in another sp. The colour of 

 these is a sordid brown ochre till the pulvilli-like scales 

 are worn off, as they generally appear to be when the 

 insect has been long on the wing; and naples yellow 

 beneath. Portions of the abdominal fold above and below 

 in one species are of a shining creamy texture, as if 

 irregularly changed by some fluid. The object or purpose 

 of these <? marks is a study in itself. They are found as 

 supposed scent-organs by Mr. Frederick Moore in many 

 of the Euploeas. In the Pompeus, and Brookeana groups 

 the abdominal fold of the <? contains a quantity of brownish 

 or ochreous cottony material. Generally each fibre is longer 

 and finer in texture than that mentioned on Caligo. It is 

 quite concealed within the fold, and though attached to the 

 inner surface, is arranged apparently in tufts or bundles, 

 with the slightest adhesion, and quite invisible from the 

 outside. Indeed it would be possible to possess long 

 series of these insects, and never to discover the existence 

 of this material, especially in such an insect as Brookeana. 

 So closely is it packed, and so light and delicate are the 

 constituent parts that when pulled out with a needle, it 

 may be piled up to an extraordinary height upon the 

 wing, so as to seem impossible that the fold could have 

 contained such a mass. It is even more abundant in the 

 S S of some of the Black and Red Papilios of S. America, 

 evidencing their close relationship to the Pompeoptera. 

 These peculiar characters are not entirely absent from 

 the Heterocerous Lepidoptera ; for, in one of the noctuid 

 moths of the family of Erebiidte in the author's museum, 

 a peculiar fold or pouch is situated beneath the anterior 

 wing, close to the submedian nervure and inner margin, 

 just where the wing closes over the costa of the lower 

 wing : this is filled with a mass of long pulvilli-like 

 material. 



