IN DEFENSIVE COLORATION 351 



wing apical spot of Eastern Brazil, the chestnut ground- 

 colour of the Upper Amazon at Ega, the bold black and 

 tawny of Ecuador, Bolivia, and Peru. The Procryptic 

 colouring of the under surface differs from the mimetic 

 pattern of the upper in its perfection. The resemblance, 

 invariably to a dead leaf, is remarkably detailed and 

 beautiful. The general colouring of the upper surface 

 does indeed influence the under, but never in such a 

 manner as to interfere in any way with the cryptic effect. 

 Thus, the under surface of the dark forms from Ega and 

 Peru is mottled with rich dark shades of brown, while in 

 the pale and yellowish Protogonius from Trinidad the 

 shades are light in tint and include prominent greys and 

 yellows. Similarly in every locality a correspondence 

 between upper and under surface is at once evident, but 

 nevertheless the first always remains roughly mimetic, 

 the second beautifully cryptic. The hind wing in this 

 genus possesses a well-developed * tail ', somewhat ex- 

 panded at the end, and this is probably Directive during 

 the active condition, serving to divert attacks from the 

 body, while during profound rest it may resemble a leaf- 

 stalk and thus aid in the cryptic effect. This suggestion 

 requires for its confirmation the careful observation of 

 the living insect. 



The interpretation of the facts presented by this deeply 

 interesting genus is by no means easy. It has been 

 brought forward by Mr. R. Shelford l as an instance of 

 Pseudaposematic or Batesian Mimicry, and I have always 

 thought that it afforded some of the strongest, probably 

 the very strongest, evidence in support of the existence 

 of such resemblances among butterflies. The colouring 

 of the upper surface is undoubtedly displayed during flight, 

 and has been developed in relation to attacks made when 

 the butterfly is upon the wing. 2 The mimicked Aposematic 

 pattern would of course make the butterfly extremely 

 conspicuous, while at the same time the roughness of 

 the resemblance and different mode of flight would render 

 it easily distinguishable among the crowd of Ithomiines, 



1 At the Entomological Society, June 5, 1907. Unpublished.' 



2 See W, J. Kaye in Trans. Ent. Soc., Lond., 1906, p. 431. 



