150 THE MALAYAN PAPILIONIDE AS 
I find that in all essential characters—the form and 
texture of the wings, the length of the antenne, the 
spotting of the head and thorax, and even the peculiar 
tints and shades with which it is ornamented —it 
corresponds exactly with the other females of the 
Pammon group; and though, from the peculiar mark- 
ing of the fore wings, it has at first sight a very dif- 
ferent aspect, yet a closer examination shows that 
every one of its markings could be produced by slight 
and almost imperceptible modifications of the various 
allied forms. I fully believe, therefore, that I shall 
be correct in placing P. Romulus as a third Indian 
form of the female P. Pammon, corresponding to P. 
Melanides, the third form of the Malayan P. Theseus. 
I may mention here that the females of this group 
have a superficial resemblance to the Polydorus ‘group 
of Papilios, as shown by P. Theseus having been con- 
sidered to be the female of P. Antiphus, and by P. 
‘Romulus being arranged next to P. Hector. There is 
no close affinity between these two groups of Papilio, 
and I am disposed to believe that we have here a 
case of mimicry, brought about by the same causes 
which Mr. Bates has so well explained in his account 
of the Heliconidee, and which has led to the singular 
exuberance of polymorphic forms in this and_ allied 
groups of the genus Papilio. I shall have to devote 
a section of my essay to the consideration of this 
subject. 
The third example of polymorphism I have to bring 
forward is Papilio Ormenus, which is closely allied 
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