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 Idaeoides 

 from the Philippine Islands, must, when on the wing, 

 perfectly resemble the Hestia Leuconoe 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 

 DanaidaB 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 Danaidse, are abundant in individuals, 



