42 NATURAL SELECTION in 



to the branches, that until it moves it is absolutely invisible ! 

 An allied species (0. concentricus) is found only at Para, on a 

 distinct species of tree, the bark of which it resembles with 

 equal accuracy. Both these insects are abundant, and we 

 may fairly conclude that the protection they derive from this 

 strange concealment is at least one of the causes that enable 

 the race to nourish. 



Many of the species of Cicindela, or tiger beetle, will 

 illustrate this mode of protection. Our common Cicindela 

 campestris frequents grassy banks, and is of a beautiful green 

 colour, while C. maritima, which is found only on sandy sea- 

 shores, is of a pale bronzy yellow, so as to be almost invisible. 

 A great number of the species found by myself in the Malay 

 islands are similarly protected. The beautiful Cicindela 

 gloriosa, of a very deep velvety green colour, was only taken 

 upon wet mossy stones in the bed of a mountain stream, where 

 it was with the greatest difficulty detected. A large brown 

 species (C. heros) was found chiefly on dead leaves in forest 

 paths ; and one which was never seen except on the wet mud 

 of salt marshes was of a glossy olive so exactly the colour of the 

 mud as only to be distinguished, when the sun shone, by its 

 shadow ! Where the sandy beach was coralline and nearly 

 white, I found a very pale Cicindela ; wherever it was volcanic 

 and black, a dark species of the same genus was sure to be 

 met with. 



There are in the East small beetles of the family Bupres- 

 tidae which generally rest on the midrib of a leaf, and the 

 naturalist often hesitates before picking them off, so closely 

 do they resemble pieces of bird's dung. Kirby and Spence 

 mention the small beetle Onthophilus sulcatus as being like 

 the seed of an umbelliferous plant; and another, a small 

 weevil, which is much persecuted by predatory beetles of the 

 genus Harpalus, is of the exact colour of loamy soil, and was 

 found to be particularly abundant in loam pits. Mr. Bates 

 mentions a small beetle (Chlamys pilula) which was undis- 

 tinguishable by the eye from the dung of caterpillars, while 

 some of the Cassidae, from their hemispherical forms and pearly 

 gold colour, resemble glittering dew-drops upon the leaves. 



A number of our small brown and speckled weevils at the 

 approach of any object roll off the leaf they are sitting on, at 



