156 NATURAL HISTORY. [cH. X. 



also caused Messrs. Kirby and Spence to observe, 

 " To such perfection, indeed, has nature in them 

 carried her mimetic arts, that you would declare, 

 upon beholding some insects, that they had robbed 

 the trees of their leaves to form for themselves 

 artificial wings, so exactly do they resemble them 

 in their form, substance, and vascular structure ; 

 some representing green leaves, and others those 

 that are dry and withered; nay, sometimes this 

 mimicry is so exquisite, that you would mistake the 

 whole insect for a portion of the branching spray 

 of a tree." 



There are also some other species, which are wing- 

 less, and therefore called walking-sticks. Through- 

 out their metamorphoses these are stated to be more 

 especially found only in the colder latitudes, while 

 the winged species inhabit only the warmer parts 

 of the world. They also bear great likeness to 

 branches of trees, which induced one of the formei 

 mentioned authors to say, " I have one from Brazil, 

 eight inches long, that, unless it was seen to move, 

 could scarcely be conceived to be any thmg else than 

 a small branch with its spray ; the legs, as well as 

 the head, having their little snags and knobs, so that 

 no imitation can be more perfect." 



Their habits have been stated to differ from those 

 of the former tribe. These insects live on the trees, 

 on the leaves of whicli they feed by night ; they are 

 very unsocial in their mode of life, being rarely 

 found more than two in company ; during the day 

 they are found lying close under the surface of the 

 leaves of plants, with their forelegs stretched out 

 before, parallel with their antennae, or feelers, as if 

 to protect them from enemies. One extraordinary 

 circumstance has been mentioned with respect to 

 these insects, that is, if by any violence they should 

 lose a limb, the same is reproduced, when "they un- 

 dergo their change of skin, as occurs among Crus- 

 tacea and spiders. 



