_Papilio Pammon_, L., offers a somewhat similar case. The female was described by Linnæus as _P. Polytes_, and was considered to be a distinct species till Westermann bred the two from the same larvæ (see Boisduval, ‘Species Générales des Lépidoptères,’ p. 272). They were therefore classed as sexes of one species by Mr. Edward Doubleday, in his ‘Genera of Diurnal Lepidoptera,’ in 1846. Later, female specimens were received from India closely resembling the male insect, and this was held to overthrow the authority of M. Westermann’s observation, and to reestablish _P. Polytes_ as a distinct species; and as such it accordingly appears in the British Museum List of Papilionidæ in 1856, and in the Catalogue of the East India Museum in 1857. This discrepancy is explained by the fact of _P. Pammon_ having two females, one closely resembling the male, while the other is totally different from it. A long familiarity with this insect (which, replaced by local forms or by closely allied species, occurs in every island of the Archipelago) has convinced me of the correctness of this statement; for in every place where a male allied to _P. Pammon_ is found, a female resembling _P. Polytes_ also occurs, and sometimes, though less frequently than on the continent, another female closely resembling the male; while not only has no male specimen of _P. Polytes_ yet been found, but the female (_Polytes_) has never yet been found in localities to which the male (_Pammon_) does not extend. In this case, as in the last, distinct species, local forms, and dimorphic specimens have been confounded under the common appellation of varieties.