532 THE ZOOLOGIST. 



The well-known Tropical American butterflies belonging to the 

 genus Ageronia, which flatten their similarly coloured wings on 

 the lichen-covered trunks, are also described as to " invariably 

 rest head downwards."* Mr. Geo. Windsor Earl relates that at 

 Sourabaya he saw Lizards attack large moths, but they were not 

 always successful, " unless they could manage to seize the head, 

 when, after a struggle of a few minutes, the little reptile would 

 bear away his prey to devour at his leisure."! Weismann seems 

 more or less of this opinion also, for he observes : — " These 

 markings are composed of two parts, the upper of which is on 

 the fore wings, while the lower one is on the hind wings. The 

 butterfly when at rest must therefore keep the wings in such a 

 position that the two parts of each marking exactly correspond, 

 for otherwise the character would be valueless; and, as a matter 

 of fact, the wings are held in the approximate position, although 

 the butterfly is, of course, unconscious of what it is doing. 

 Hence a mechanism must exist in the insect's brain which com- 

 pels it to assume this attitude, and it is clear that the mechanism 

 cannot have been developed before the peculiar manner of holding 

 the wings became advantageous to the butterfly, viz. before the 

 similarity to a leaf had made its first appearance."! We should 

 opine, however, that the Kallima is exercising some volition 

 in seeking the environment of the withered leaves with which 

 the under surface of its wings approximate, an action we have 

 seen pursued by other butterflies with reference to different 

 surroundings, and that the exact corresponding position of the 

 wings is hereditary, and perhaps now describable as unconscious 

 cerebration, or reflex action. Animals do not all use the same 

 means for protection ; the method may be different, but the 



the description of the habits of another species of the genus as given by 

 Wallace in his ' Malay Archipelago.' 



* H. C. Dent, ' A Year in Brazil,' p. 384. 



\ ' The Eastern Seas,' p. 53. 



I ' Essays upon Heredity,' &c, Eng. transl., vol. i. p. 287. — Weismann 

 adds that " even this protective resemblance to or mimicry of a leaf is not 

 perfect, for out of sixteen specimens in the collections at Amsterdam and 

 Leyden which he examined, he could not find a single one which had more 

 than two lateral veins on one side of the midrib of the supposed leaf, or 

 more than three upon the other side ; while about six or seven veins should 

 have been present on each side " (ibid. p. 315). 



