246 DARWINISil CHAP. 



Other Examples of Mimicry among Lepidoptera. 



In tropical Asia, and eastward to the Pacific Islands, the 

 Danaidre take the place of the Heliconidte of America, in their 

 abundance, their conspicuousness, their slow flight, and their 

 being the subjects of mimicry. They exist under three 

 jDrincipal forms or genera. The genus Euplsea is the most 

 abundant both in species and individuals, and consists of fine 

 broad -winged butterflies of a glossy or metallic blue -black 

 colour, adorned with jDure Avhite, or rich blue, or dusky mark- 

 ings situated round the margins of the wings. Danais has 

 generally more lengthened -ttdngs, of a semitransparent greenish 

 or a rich brown colour, with radial or marginal pale spots ; 

 while the fine Hestias are of enormous size, of a papery or 

 semitransparent white colour, Avith dusky or black spots and 

 markings. Each of these groups is mimicked by various 

 species of the genus Papilio, usually with such accuracy that 

 it is impossible to distinguish them on the wing.^ Several 

 species of Diadema, a genus of butterflies allied to our 

 Vanessas, also mimic species of Danais, but in this case the 

 females only are aff'ected, a subject which will he discussed in 

 another chapter. 



Another protected group in the Eastern tropics is that of 

 the beautiful day-flying moths forming the family Agaristidae. 

 These are usually adorned with the most brilliant colours or 

 conspicuous markings, they fly slowly in forests among the 

 butterflies and other diurnal insects, and their great abundance 

 sufficiently indicates their possession of some distastefulness 

 which saves them from attack. Under these conditions we 

 may expect to find other moths which are not so protected 

 imitating them, and this is the case. One of the common and 

 wide-ranging species (Opthalmis lincea), found in the islands 

 from Amboyna to Xew Ireland, is mimicked in a Avonderful 

 manner by one of the Liparicla3 (the family to which our 

 common " tussock " and " vapourer " moths belong). This is 

 a new species collected at Amboyna during the voyage of the 

 Challenger, and has been named Artaxa simulans. Both 



1 See Trans. Linn. Soc, vol. xxv. Wallace, on Variation of Malayan 

 Papilionida' ; and, Wallace's Coiitfiljidums to Xati'ral Selection, chaps, iii. and 

 iv., where full details are given. 



