194 STUDIES, SCIENTIFIC AND SOCIAL chap. 



habit of stretching themselves out obliquely when in 

 repose, attached only by the clasping legs at the further 

 extremity, and will remain stiff and motionless in this 

 position for hours. The little protuberances on the body, 

 their colour and attitude, give them so exactly the appear- 

 ance of twigs of the living tree, that we may easily con- 

 ceive the advantage this disguise must be to them ; for it 

 is certain that many will escape destruction when more 

 conspicuous insects will be devoured. 



Among the extensive group of the Coleoptera, the 

 examples of a protective disguise are literally innumerable. 

 In the tropics, every fallen tree swarms with beetles, and 

 a large number of these so closely resemble the bark to 

 which they cling, that it requires a close examination to 

 detect them. The families of the Longicorns and Curculios 

 furnish the greater part of these ; and among the former, 

 that which wears perhaps the most perfect disguise is the 

 Onycliocerus scorpio. This beetle is common in South 

 America, and was found abundantly by Mr. Bates on the 

 banks of the Amazon, but always clinging to the rough 

 bark of one kind of tree, called by the natives Tapiriba. 

 This bark was so closely imitated by the beetle itself, — its 

 elytra and thorax being tubercled and coloured so as 

 exactly to match it, and the insect clinging so closely as 

 to form, apparently, one surface with the tree, that Mr. 

 Bates assures me it was often absolutely impossible to 

 detect it by the closest inspection as long as it remained 

 motionless 1 



Many of the Tiger beetles, although they are such con- 

 spicuous and beautiful objects in our cabinets, are well 

 disguised when in their natural stations. Our commonest 

 species, Cidndela campestris, is fond of grassy banks, where 

 its green colour makes it difficult to see it. Cidndela 

 maritima is almost exactly the same colour as the sandy 

 shores it haunts. The large Cidndela heros frequents the 

 mountainous forests of Celebes, where its brown colour 

 exactly matches with the dead leaves that cover the 

 ground. The magnificent velvety-green Cidndela gloriosa 

 was captured only on wet moss-covered rocks in the bed 

 of a mountain torrent in the island of Celebes, where it 



