llX' TIIK EVOLUTION THEORY 



^vhicll liJis oufi' \>vvi\ pot'ked at, or sqiicczeil by the bill of a bird, 

 is (loonu'd to <lii'. l^ut if two iiR'(lil)le species which resemble each 

 other inhabit tlie same area they will be regarded by the birds as 

 one and the same, and if tive or more inedible species resemble each 

 other all live will present the same appearance to the bird, and it 

 will not reipiire to repeat on the other four the experience of 

 unpalatability it has gained from one. Thus the total of five species 

 will be uo more severely decimated by the young birds than each of 

 them would have been if it had occurred alone ; the same number 

 of \ictims of experiment, which are necessary every year in the 

 education of the young birds, will, when all five species look alike, 

 be divided among the whole ' mimicry ring,' as we may say. The 

 advantage of the resemblance is thus obvious, and w^e can understand 

 why a pi'ocess of selection should develop among such inedible 

 species which should result in their being readily mistaken for one 

 another : we can understand why, in the neighbourhood of Fritz 

 Miiller's home, Blumenau, in the province of Santa Catarina in South 

 Brazil, the Danaida?, species of Lycorea ; the Heliconiidae, Heliconius 

 eucrate and Eaeides isahella; and the Neotropinas, Mechanitis 

 lyshnnia and species of Melincea, should all exhibit the same colours, 

 brown, black and yellow, in a similar pattern, on similarly shaped 

 wings. The agreement is by no means perfect in detail, but it can 

 be noticed in all parts of South America inhabited by species of these 

 genera, and the same differences Avliich distinguish, for instance, the 

 two species of Heliconius flying in two different regions, also 

 distinguish the two species of Ev.eides and the two species of 

 Mechanitis. In Honduras we find the same mutually protective 

 company of inedible genera as in Santa Catarina, but represented 

 by other species, which all differ from the species in Santa Catarina 

 in the same characters, as, for instance, that they have two instead 

 of one pale yellow cross-stripe on the anterior wings. The species 

 are : Lycorea atergatis, Heliconius telchinia, Eueides clynastes, 

 Mechanitis doryssus, and Melincea imitata^. In the environs of 

 Bahia this mimicr}^ ring consists of the following species : Heliconius 

 eucrate, Lycorea halia, Mechanitis lysimnia, and Melinciu ethra, as 

 figured on PI. II, Fig. 12, iv, and such a mutual assurance society 

 has always one or other edible species as mimic. The larger the 

 mimetic assurance company is, the less harm can mimics do to it. 

 In the case figured it is tw^ o Pieridse already known to us that have 

 fairly well assumed the Heliconiid guise, namely, Dismorphia astynome 



' According to Poulton's report in Naf.ure, July 6, 1889, of ' Sykes, Natural Selection 

 in the Lepidoptera,' Trans. Mamhester Microscop. Soc. 1897, p. 54. 



