OCR Text |
Show 480 PROF. J. O. WESTWOOD ON INDIAN BUTTERFLIES. [Apr. 5, a female specimen (of which sex many more specimens have obtained) having the upperside of the wings dark brown, with a small whitish dot at the extremity of the discoidal cell of the fore wings, and a row of small submarginal white spots (of different sizes) parallel to the outer margin of the fore wing, which is marked with slight marginal white incisions. The hind wings on the upperside have a broad fascia of dirty greenish-white colour, strongly irrorated with blackish scales, extending all across the middle of the wing and into the discoidal cell, and divided by the longitudinal veins into seven longitudinal patches ; the outer margin of this fascia is scalloped, and is followed by a submarginal row of seven large white lunules, the one next the anal angle being divided in the middle, and with very slight marginal white incisures between the veins. On the underside the pale-coloured portion of the hind wings (Plate XLIV. fig. 4) extends much further towards the base of the wings, and is also partially seen on the inner portion of the fore wings ; the sub-marginal lunules are also larger. Various specimens of this female varied from 4-| to 5-i- inches in expanse. It is to be further noticed that the hind wings are rounded in form, with the hind margins slightly scalloped. From the preceding observations it will be seen that, in addition to the different dimensions, P. castor is distinguished by the large, nearly white 4-partite spot between the outer angle and the disk of the hind wings, which are elongate-ovate in form ; whilst P. pollux has rounded hind wings, nearly the whole of the disk of which bears a broad 7-partite band of strongly irrorated greenish-white colour, separated by the veins, and gradually shaded off into the dark base of the wings, and with a submarginal row of whitish lunules. In the extensive genus Papilio there is great diversity in the extent of difference between the two sexes of the same species. Thus, whilst in some (P. machaon, P. podalirius, &c.) it is almost impossible, without microscopical examination, to distinguish the male from the female, other species differ so greatly in size, shape, colour, and markings as to lead to the opposite sexes being easily mistaken (as, indeed, in many instances has been the case) for distinct species. The decided determination of this question is, of course, only to be obtained by an examination of the insects in nature, either by observing their actual sexual connexion, or by rearing the two sexes from the same batch of eggs. Beyond this, of course, the assertion of the sexual connexion between two dissimilar insects must of course be conjectural; and conjecture has been at work with the two insects under consideration. The late Mr. E. Doubleday introduced these insects as two distinct species in his portion of the ' Genera of Diurnal Lepidoptera,' P. castor being his 72nd species (p. 12), placed between P. erithonius, Cramer, and P. phestus, Bdv. & Guerin, ' Voy. Coquille, Ins.' pi. 14. f. 2 (to which latter it bears considerable resemblance in form) ; whilst P. pollux is his 264th species, placed between P. dissimilis, Linn. (P. panope, Linn., $ ) , and P. palephales,Westw. 'Arc. Ent.' t. /9. f. I, 2, from Manilla. |