168 Phenomena of Variation and Geographical Distribution. 



Memon, L., is one of the most striking, as it exhibits the mixture of 

 simple variability, local and polymorphic forms, all hitherto classed 

 under the common title of varieties. The polymorphism is strikingly 

 exhibited by the females, one set of which resemble the males in form, 

 with a variable paler coloring ; the others have a large spatulate tail 

 to the hinder Aving, and a distinct style of coloring, which causes 

 them closely to resemble P. Coon, a species of which the sexes are alike 

 and inhabiting the same countries, but with which they have no direct 

 affinity. The tailless females exhibit simple variability, scarcely two 

 being found exactly alike even in the same locality. The males of the 

 island of Borneo exhibit constant differences of the under surface, and 

 may therefore be distinguished as a local form, while the continental 

 sj)ecimens, as a whole, offer such large and constant differences from 

 those of the islands that I am inclined to separate them as a distinct 

 species — P. Androgens, Cr. We have here, therefore, distinct species, 

 local forms, polymorphism, and simple variability, which seem to me 

 to be distinct phenomena, but which have been hitherto ail classed 

 together as varieties. I may mention that the fact of these distinct 

 forms being one species is doubly proved. The males, the tailed and 

 tailless females, have all been bred from a single group of the larvae, 

 by Messrs. Payen and Bocarme, in Java, and I myself captured in 

 Sumatra a male P. Memnon, L., and a tailed female P. Achates, Cr., 

 " in copuJa." 



Papillo Pammon, L., offers a somewhat similar case. The female 

 was described by Linnaeus as P. Polytes, and was considered to be a 

 distinct species till Westermann bred the two from the same larvse (see 

 Boisduval, " Species Generales des Lepidopteres," p. 272). They were 

 therefore classed as sexes of one species by Mr. Edward Doubleday, in 

 iiis " Genera of Diurnal Lepidoptera," in 184G. Later, female speci- 

 mens were received from India closely resembling the male insect, and 

 this was held to overthrow the authority of M. Westermann's observa- 

 tion, and to re-establish P. Polytes as a distinct species ; and as such it 

 accordingly appears in the British Museum List of Papilionidse in 1856, 

 and in the Catalogue of the East India Museum in 1857. This discrep- 

 ancy is explained by the fact of P. Pammon having two females, one 

 closel}^ rasembling the male, while the other is totally different from it. 

 A long femiliarity with this insect (which replaced b}^ local forms or 

 by closely allied species, occurs in every island of the archii^elago) has 

 €onviueed 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, ajiother female closely resembling the male ; while not only 



