Mimicry 



is heightened by a dark streak Which runs fr6m-wing-tfp 

 to tail, giving the appearance of a midrib. And this is 

 not all. We mentioned that there are clear spots on the 

 wings. In the resting position these spots coincide with 

 one another on the folded wings, so that there appears to be 

 a hole through them, just as there might be through an old, 

 damaged leaf. Keen eyes of bird or man are necessary to 

 detect this wonderful mimic when it is enjoying a siesta. 



The leaf-butterfly is not the only insect with the out- 

 ward form of a leaf. There is an African insect, closely 

 related to the grasshopper, which bears a remarkable 

 resemblance to a green leaf. These creatures have 

 flattened bodies, and their wing-cases are leaf-like in 

 appearance and colour, as also are their fore and middle 

 legs. The hinder edges of their wing-cases, as they lie 

 touching one another on the insects' backs, resemble the 

 midrib of the leaf. The insects are slow-moving creatures ; 

 in fact they often remain for hours together without 

 moving, a habit which renders their resemblance to green 

 leaves of the plants on which they feed still more 

 remarkable. An entomologist who studied these freaks 

 of nature in the Seychelles relates that when food is 

 scarce " they frequently nibbled pieces out of one another, 

 just as they might have done out of leaves," and that they 

 always feasted off those parts which resembled leaves. 



Much better known are the stick insects, also relatives 

 of the grasshopper. These creatures, which may be 

 veritable insect giants, or, on the contrary, dwarfs, always 

 bear a very striking resemblance to the stems of the 

 plants on which they feed. They may be winged or 

 wingless ; but, in the former event, the wings are always 

 folded tightly to the body so as to heighten their general 

 resemblance to a stick. Their long, thin legs are 

 frequently covered with spines, if they happen to belong 

 to a species which feeds on a spiny tree, or with mossy- 

 looking growths, if they frequent moss-covered trees. 



Professor Drummond naYvely described a stick insect 



10 1 



