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ILLUSTRATI VE OF NATURAL SELECTION. 147 
which the name P. Androgeus (Cramer) may be ap- 
plied. 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 all 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 larva, by Messrs. Payen and Bocarmé, in Java, 
and I myself captured, in Sumatra, a male P. Memnon, 
and a tailed female P. Achates, under circumstances 
which led me to class them as the same species. 
Papilio Pammon offers a somewhat similar case. 
The female was described by Linnzus as P. Polytes, 
and was considered to be a distinct species till Wes- 
termann bred the two from the same larve (see 
Boisduval, ‘‘ Species Général des Lépidoptéres,” 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 in- 
sect, and this was held to overthrow the authority of 
M. Westermann’s observation, and to re-establish P. 
Polytes as a distinct species; and as such it accord- 
ingly appears in the British Museum List of Papilio- 
nid 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 re- 
sembling the male, while the other is totally different 
from it. A long familiarity with this insect (which 
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