LECTURE Y 

 TRUE MIMICRY 



Mimicry : its discovery by Bates— Heliconiidae and Pieridse— Danaides PapUio 



merope and its five females— The females lead the way— Species with mimicry in both 

 sexes — Objections— Enemies of butterflies— The immunity of the models— Poison ousness 



of the food-plants of immune species — Several mimics of the same immune species 



Persecuted species of the same genus resemble quite different models — Elymnias 



Degree of resemblance— Differences between the caterpillars of the model and the copy 

 — The same resemblance arrived at by different ways — Transparent-winged butterflies 

 — The gradually increasing resemblance points to causes operating mechanically — 

 Parity of the mimetic species — Danger to the existence of the species not a necessary 

 condition of mimetic transformation — Papilio meriones and Papilio merope — Comparison 

 with the dimorphic caterpillars — Papilio turnus — ' Mimicry rings ' of immune species — 

 Danais erippus and Limenitis ardiippus — Marked divergence of mimetic species from their 

 nearest relatives — Mimicry in other insects — Imitators of ants and bees. 



Let us now turn to the most remarkable of all protective form- 

 and colour-adaptations, the so-called Mimicry, including all cases of 

 the imitation of one animal by another, which we came to know first 

 through Bates, and to a fuller understanding of which A. R. Wallace 

 and Fritz Muller have especially contributed. 



While the English naturalist, Bates 1 , was collecting and observ- 

 ing on the banks of the Amazons — as he did for twelve years — it 

 sometimes occurred that, among a swarm of those gaily coloured, 

 quaintly shaped butterflies, the Heliconiidae (PL II, Fig. 13), he 

 caught one which, on closer examination, proved to be essentially 

 different from its numerous companions. It was certainly like them 

 both in colour and form, but it belonged to quite a different family of 

 butterflies, that of the Pieridse or Whites (PL II, Fig. 19). These 

 whites with the colours of the Heliconiidae always occurred singly in 

 swarms of the latter form, and Bates found that, in the different 

 districts of the Amazon, they always resembled in a striking manner 

 the species of Heliconiidae there prevalent. Many of them had been 

 previously known to entomologists, and because they diverged so far 

 from the usual type of the Pieridse, especially in the form of the 

 wing, the name Dysmorphia, the 'mis-shapen/ had been given to 

 them, although the meaning of this ' mis-shapenness ' long remained 



1 Contributions to an Insect Fauna of the Amazon Valley, Trans. Linn. Soc, Vol. 

 XXIII, 1862. 



