vi DEFENCES QF INSECTS 209 



small weevil mercilessly persecuted by ground-beetles 

 abounds in pits of a loamy soil, of the same colour 

 precisely with itself, undoubtedly facilitating the 

 escape of many from their foe. A scarce British 

 weevil, by its grey colour spotted with black, is an 

 equally good counterpart of the locality where it 

 generally seems to roam, which consists of white 

 sand mixed with black earth. 



In some cases a species confine themselves entirely 

 to one species of tree, whose bark they simulate in 

 colour and rugosity. They are excessively abundant, 

 and surely it cannot be considered exaggerated to 

 regard the protection derived from the resemblance 

 as a factor, and no small one, in the flourishing 

 condition of the race. 



Numbers of our weevils and other beetles when 

 alarmed drop off the leaves on which they are sitting, 

 at the same time rolling themselves into little lumps 

 or balls. It is useless to look for them on the 

 ground, where they lie motionless amid stones and 

 earth-pellets, the appearance of which they simulate 

 exactly. 



The fact is well known that however gay the 

 upper surfaces of the wings of butterflies may be, the 

 undersides are nearly always sober, often very dull 

 and obscure, and in some instances have been observed 

 to be like the surfaces whereon the insects customarily 

 rest. This arrangement of colour is eminently'pro- 

 tective, because during prolonged repose a butterfly 

 takes care to hold its wings raised perpendicularly 

 over the back, effectually to conceal its lovely but 

 treacherous possession. Moths usually have their 



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