MIMICRY IN mSECT LIFE. '89 



{Fig. 3.) The "Leaf Butterfly" [Kallima philarchus) is a very 

 beautiful example of protective resemblance. While it is on the 

 wing the bright blue tints of the upper surface render it a con- 

 spicuous insect, but when the wings are folded together in the resting 

 position, their form and colouring exactly imitates a withered leaf. 

 The markings take the form of the midrib and veins of the natural 

 leaf, while the resemblance is heightened by a blunt tail-like process 

 from the hind wing, which takes the place of the stalk of the leaf. 

 It even copies the frequent blemishes that are found on a dead leaf. 

 There are often irregular dark-coloured blotches, such as are caused 

 bjr fungus diseases of the plant, and in some examples there is a 

 small transparent spot suggesting a hole in the leaf. In natural 

 history books this insect is usually represented perched on a leafy 

 branch, in which position the brown tints of the wings would not 

 harmonize with their surroundings. But in nature the insect more 

 usually settles head downwards on the trunk of a tree, and it has 

 acquired the habit of swaying gently from side to side. It might 

 then be mistaken very easily for a detached leaf that in its fall has 

 hitched up m a cobweb and is being shaken by the breeze. 



Then there are many insects that Jiabitually rest on the bark of 

 trees. These have assimilated themselves most perfectly to such 

 surroundings. And as bark is very frequently spotted and mottled 

 with gray and greenish lichens, so these particular insects are 

 usually variegated with similar markings. Moths of various kinds, 

 certain beetles, several Homoptera, and a few grasshoppers exhibit 

 this form of protective resemblance. 



{Fig. 4.) Even such a large and bulky insect as our large 

 Wood-boring Moth {Duomitus leuconotus) , which has a wing expanse 

 of nearly 8 inches, can conceal itself very successfully by its 

 resemblance to a patch of lichen-covered bark. Its wings are 

 closely mottled with gray and black. Another large moth {Elphos 

 hymenaria), with similar markings, rests with outstretched wings 

 on the trunks of trees, where it is in perfect harmony with its 

 surroundings. 



The large " Hawk Moth " {Pseudosphinx discistriga) becomes 

 practically invisible when resting in similar situations. 



A large beetle, common in the Kandy districts, is ornamented 

 with irregular streaks of light and dark brown, and looks 

 curiously like the fibrous surface of wood where some branch has 

 been torn off. 



{Fig. 5.) Another beetle {Alaus speciosus), which, when seen by 

 itself, appears to be most conspicuously marked, when resting — 

 as it frequently does — on the charred stump of some tree in a newly 

 burned clearing, would be mistaken for an irregular patch of white 

 ash. But in this case it is doubtful if the apparent adaptation is 

 real, for the insect cannot of necessity confine itself to recently 

 charred stumps , and the gradual evolution of this pattern must date 



