COLOUK OF INSECTS. 13 



able information as to their habits, mode of life, and variety 

 of colouring : — 



" On the sandy beach I found two species of Tetracha, a 

 genus of Tiger Beetles, which have remarkably large heads, and 

 are found only in hot climates. They come forth at night, in 

 the daytime remaining hid in their burrows several inches deep 

 in the light soil. Their powers of running exceed everything I 

 witnessed in this style of insect locomotion. They run in a 

 serpentine course over the smooth sand, and when closely pur- 

 sued by the fingers in the endeavour to seize them, are apt to turn 

 suddenly back, and thus baffle the most practised hand and eye. 



" I afterwards became much interested in these insects on 

 several accounts, one of which was that they afforded an illus- 

 tration of a curious problem in natural history. One of the 

 Caripi species {Tetracha nocturna of Dejean) was of a pallid 

 hue, like the sand over which it ran ; the other was a brilliant 

 copper-coloured kind {Tetracha pallipes of King). Many insects 

 whose abode is the sandy beaches are white in colour ; I found 

 a large earwig and a mole cricket of this hue very common in 

 these localities. 



" Now, it has been often said, when insect's, lizards, snakes, 

 and other animals are coloured so as to resemble the objects on 

 which they live, that such is a provision of Nature, the assimila- 

 tion of colours being given in order to conceal the creatures 

 from the keen eyes of insectivorous birds and other animals. 

 This is no doubt the right view, but some authors have a diffi- 

 culty in the explanation on account of the assimilation of colours 

 being exhibited by some kinds and not by others living in com- 

 pany with them ; the dress of some species being in striking 

 contrast to the colours of their dwelling-place. 



"One of our Tetrachas is coloured to resemble the sand, 

 whilst its sister species is a conspicuous object on the sand ; the 

 white species, it maybe mentioned, being much more swift of 

 foot than the copper-coloured one. The margins of these sandy 

 beaches are frequented throughout the fine season by flocks of 

 sandpipers, who search for insects on moonlit nights as well as 

 by day. If one species of insect obtains immunity from their 

 onslaughts by its deceptive resemblance to the sandy surface 

 on which it runs, why is not its sister species endowed in the 

 same way ? 



