ILLUSTRATIVE OF NATURAL SELECTION. 181 
from the same country, just as Papilio Marcareus re- 
sembles Danais Aglaia in Malacca, and (according to 
Dr. Horsfield’s figure) still more closely in Java. The 
Indian Papilio Agestor closely imitates Danais Tytia, 
which has quite a different style of colouring from the 
preceding; and the extraordinary Papilio Ideoides 
from the Philippine Islands, must, when on the wing, 
perfectly resemble the Hestia Leuconoé of the same 
region, as also does the Papilio Delessertii imitate 
the Ideopsis daos from Penang. Now in every one of 
these cases the Papilios are very scarce, while the 
Danaidz which they resemble are exceedingly abun- 
dant—most of them swarming so as to be a positive 
nuisance to the collecting entomologist by continually 
hovering before him when he is in search of newer and 
more varied captures. Every garden, every roadside, 
the suburbs of every village are full of them, indicating 
very clearly that their life is an easy one, and that 
they are free from persecution by the foes which keep 
down the population of less favoured races. This 
superabundant population has been shown by Mr. 
Bates to be a general characteristic of all American 
groups and species which are objects of mimicry; and. 
it is interesting to find his observations confirmed by 
examples on the other side of the globe. 
The remarkable genus Drusilla, a group of pale- 
coloured butterflies, more or less adorned with ocellate 
spots, is also the object of mimicry by three distinct 
genera (Melanitis, Hyantis, and Papilio). These in- 
sects, like the Danaide, are abundant in individuals, 
