ix WARNING COLORATION AND MIMICRY 255 



Although the Heliconida? present, on the whole, many 

 varieties of coloration and pattern, yet, in proportion to the 

 number of distinct species in each district, the types of 

 coloration are few and very well marked, and thus it becomes 

 easier for a bird or other animal to learn that all belonging to 

 such types are uneatable. This must be a decided advantage to 

 the family in question, because, not only do fewer individuals 

 of each species need to be sacrificed in order that their enemies 

 may learn the lesson of their inedibility, but they are more 

 easily recognised at a distance, and thus escape even pursuit. 

 There is thus a kind of mimicry between closely allied species 

 as well as between species of distinct genera, all tending to the 

 same beneficial end. This may be seen in the four or five 

 distinct species of the genus Heliconius which all have the same 

 peculiar type of coloration — a yellow band across the upper 

 wings and radiating red stripes on the lower, — and are all found 

 in the same forests of the Lower Amazon ; in the numerous 

 very similar species of Ithomia with transparent wings, found 

 in every locality of the same region ; and in the very numerous 

 species of Papilio of the " iEneas " group, all having a similar 

 style of marking, the resemblance being especially close in 

 the females. The very uniform type of colouring of the 

 blue -black Euplaeas and of the fulvous Acrseas is of the 

 same character. 1 In all these cases the similarity of the 

 allied species is so great, that, when they are on the wing 

 at some distance off, it is difficult to distinguish one species 

 from another. But this close external resemblance is not 

 always a sign of very near affinity ; for minute examination 

 detects differences in the form and scalloping of the wings, in 

 the markings on the body, and in those on the under surface 

 of the wings, which do not usually characterise the closest allies. 

 It is to be further noted, that the presence of groups of very 

 similar species of the same genus, in one locality, is not at all 

 a common phenomenon among unprotected groups. Usually 

 the species of a genus found in one locality are each well 

 marked and belong to somewhat distinct types, while the 



1 This extension of the theory of mimicry was pointed out by Professor 

 Meldola in the paper already referred to ; and he has answered the objections 

 to Dr. F. Midler's theory with great force in the Annals and Mag. of Nat. 

 Hist, 1882, p. 417. 



