14 



AFRICAN MIMETIC BUTTERFLIES 



it were quite straight, it would hang clear of the branch and thus fail to represent an attached 

 leaf. There is a little scallop or hollow on the margin of the fore-wings at the base, which 

 serves to conceal the head of the butterfly, which is very small for its size, and the long 

 antennae are carried back and hidden between the folded wings. When sitting on a twig in 

 the manner described, the insect is to all appearance a perfectly dry leaf — yet it is evident 

 that its chances of escape would be much increased if it were surrounded by real dry leaves 

 instead of by green ones ; for if, when pursued, it took refuge in a growing bush, it could 

 hardly fail to be still a conspicuous object. Marvellous to relate, it does possess the habit 

 of almost invariably entering a bush loaded with dead leaves, and is so instantly lost to 

 sight, owing to its close resemblance to all the surrounding objects, that I doubt if the most 

 vigilant flycatcher could detect it. I have myself often been utterly puzzled. I have watched 

 it settle apparently in a very conspicuous situation, a few yards off, but on crawling carefully 

 up to the spot, have been quite unable to detect any living thing. Sometimes while gazing 

 intently, a butterfly would start out from just before my eyes, and again enter another dead 

 bush a few yards off, again to be lost in the same manner. Once or twice only was I able 

 to detect it sitting, and admire the wonderful disguise which a most strange combination 

 of colour, form, and habits, enabled it instantaneously to assume. But there is yet another 

 peculiarity which adds to the concealment of this species. Scarcely two of the specimens are 

 alike in colour on the underside, but vary through all the shades of pale buff, yellow, brown, 

 and deep rusty orange which dried leaves assume ; others are speckled over with little 

 black dots like mildewed leaves, or have clusters of spots or irregular blotches, like the minute 

 fungi that attack dead leaves ; so that a dozen of these insects might settle on a perfectly 

 bare spray, and clothe it at once with withered foliage not distinguishable from that of the 

 surrounding branches ! ' 



Resemblance to inanimate objects is not, however, by any means the only disguise 

 which Lepidoptera are found to adopt. The undersides of the genus Caligo, from South 

 America, present a beautiful portrait of the face of an owl, not only the great eyes, but every 

 feather being exquisitely traced in the complicated pattern of the wings. The hind-wings 

 also form a curious fold containing the body of the insect and projecting on the under side 

 in such a way as to form a perfect representation of a beak ; and though we have not, so far 

 as I know, any such vivid description by an eyewitness as that just quoted, we may, I think, 

 fairly assume that the appearance is coupled with habits which make use of and accentuate 

 the extraordinary resemblance.^ There is an Australasian moth which, when at rest, is 

 almost indistinguishable from the head of a snake. Bates, in his ' Naturalist on the Amazons ', 

 writes : ' Along the narrow paths in the forests, an immense number of clear-winged moths 

 are found in the daytime ; mostly coloured like wasps, bees, ichneumon flies, and other 

 Hymenopterous insects. Some species of the family have opaque wings, and wear the 

 livery of different species of beetles ; these hold their wings in repose, in a closed position 

 over their bodies, so that they look like the wing-cases of the beetles they so deceptively 

 imitate.' 



1 Since the above was written, Mr. W. F. H. 

 Rosenberg has kindly given me some interesting 

 particulars oi the habits of these ' owl ' butterflies. 

 He informs me that the insects settle on tree trunks 

 in the usual manner of butterflies, i.e. with the wings 

 erect. The fore-wings are not hidden by the secon- 

 daries. In the dim light of the forest they are by no 



means easy to see when thus at rest. They are not 

 easily disturbed but are very alert, and after allowing 

 one to come near start up with a ' mighty flap ' .of 

 the wings, making the great eyes suddenly con- 

 spicuous. One could hardly imagine anything more 

 startling to an attacking bird. 



