4 SPOLIA ZEYLANICA. 
not get near enough to catch it among the trees. Later on I took 
it at Dambulla, where it was not unplentiful on the top of the rock. 
Danaids were also flying there, but there was no question of 
confusing the Papilio with them. 
Putting aside for a moment the case of Papilio polytes, to which I 
shall refer later, my impression of all these so-called cases of mimicry, 
which I have been able to see, is that the resemblances are certainly 
not sufficiently close to deceive the eye of a civilized man with little 
experience of them. For that reason I am inclined to doubt whether 
they would systematically deceive an enemy brought up among 
them, whose means of earning a livelihood depended largely upon 
the readiness with which he could distinguish between mimic 
and model. I do not wish to deny that in some cases, and upon 
occasion, the resemblance may be of service. It is quite conceivable 
that an insectivorous animal with a distaste for Danaids would, 
when confronted with a choice between Pareronia ceylonica and a 
non-mimetic species, choose the latter so long as it only saw the 
upper surface of the former. And when the mimetic resemblance 
is already established, I see no difficulty in the supposition that the 
form which exhibits it is placed at an advantage with respect to 
natural selection compared with the non-mimetic form, provided that 
such resemblance to a distasteful model is a close one. But I feel 
that there are insuperable difficulties in the way of conceiving such 
resemblance to have arisen through the operation of natural selection. 
To this subject, however, I shall have occasion to refer later. 
The Case of Papilio polytes. 
Since 1865, when Wallace’s well known memoir on ‘“‘ The Papi- 
lionidz of the Malayan Region ”’ appeared, this striking case has 
been regarded as one of the classic instances of mimicry. Excellent 
coloured representations of this species were given by that author, 
and more recently by Moore in his “‘ Lepidoptera of Ceylon.” It is 
also figured by Distant in his ‘‘ Indo-Malayan Rhopalocera,”’ but as 
these memoirs are not always readily accessible I have had prepared 
the coloured plate which will be found at the end of this paper. 
It has been made directly from the actual specimens (which were all 
fresh and perfect) by the four-colour process, and gives on the 
whole an excellent representation of the different forms shown. 
P. polytes is a fly which is abundant throughout India and Ceylon, 
occurring both on the plains and on the hills wherever are to be 
found the citronaceous plants on which the larva (PI. I., fig. 7) feeds. 
Throughout this region the male (PI. I., fig. 1) is accompanied by 
three forms of female (Pl. I., figs. 4-6), of which two are so different 
from him as to have each been regarded at some former time as a 
distinct species, and it was not until Wallace studied them that 
the polymorphic nature of these females was understood. From 
