OCR Text |
Show 1881.] PROF. J. O. WESTWOOD ON INDIAN BUTTERFLIES. 479 6. Observations on two Species of Indian Butterflies {Papilio castor and P. pollux). By J. O. WESTWOOD, M.A., F.L.S., &c. [Received February 12, 1881.] (Plates XLIV., XLV.) In the 80th plate of my 'Arcana Entomologica,' published 1st September, 1844, I represented, under the names of Papilio castor and P. pollux, two theretofore unfigured and undescribed Butterflies, which I regarded as distinct species, sent from Assam and Sylhet by the Rev. J. Staniforth and Major F. Jenkins. The first of these two Butterflies, P. castor, of which males only had been sent, is of a dark brown or nearly black colour on the upper surface of the wings, the anterior pair having no other marking on this side than very small white marks on the outer margin between the extremities of the longitudinal veins, growing gradually smaller and even obsolete from the middle of this margin to the apex of the wing ; on the upper surface of the hind wings there is a large, very pale yellowish-white patch near the outer angle, divided by the longitudinal veins into four spots (Plate X L I V . fig. 1, upperside of the hind wing). On the underside the fore wings have a very small white spot at the extremity of the discoidal cell; the minute white marginal spots described above are present, and are preceded by a row of very minute white spots close to the outer margin of the wing, and which diminish in size and become obsolete towards the apex in the same manner as the marginal dots. The hind wings on the underside have the four large spots towards the outer angle of a diminished size, the first and fourth being very small. The small white marginal incisures are preceded by a submarginal row of very small white spots, of which the middle ones are almost obliterated, whilst the one at the anal angle is duplicated (Plate X L I V . fig. 2 represents the underside of the hind wing). In some specimens the submarginal row of white spots on the hind wings are more decided and larger than in others. It is to be added that the hind wings are elongate-ovate, produced more decidedly at the extremity of the third branch of the median vein, which is, in the regularly tailed species, developed into the spatulate tail. The head and neck are dotted with white; and there are two rows of white dots on the upper surface of the abdominal segments. These male insects vary considerably in size : the expanse of the more normal individuals is 4 ^ inches; but specimens before m e vary from 3^ to 4f inches. Plate XLIV. fig. 3 represents the upper-side of the hind wing of the smallest individual, of the natural size; the large white discoidal spot is comparatively larger than usual; and there are very slight traces to be observed of a row of submarginal white spots represented by a few scales. It is from Sylhet. The second of m y supposed species {P. pollux) was figured from |