216 MEANS OF DEFENCE OF INSECTS. 



I. The principal passive means of defence with which 

 insects are provided, are derived from their colour and 

 form, by which they either deceive, dazzle, alarm, or an- 

 noy their enemies ; or from their substance, involuntary 

 secretions, vitality, and numbers. 



They often deceive them by imitating various sub- 

 stances. Sometimes they so exactly resemble the soil 

 which they inhabit, that it must be a practised eye which 

 can distinguish them from it. Thus, one of our scarcest 

 British weevils (Curculio nebulosus\ by its gray colour 

 spotted with black, so closely imitates the soil consisting 

 of white sand mixed with black earth, on which I have 

 always found it, that its chance of escape, even though 

 it be hunted for by the lyncean eye of an entomologist, 

 is not small. Another insect of the same tribe ( Thyla- 

 cites scabrtculus), of which I have observed several species 

 of ground-beetles, (Harpalus, &c.) make great havoc, 

 abounds in pits of a loamy soil of the same colour pre- 

 cisely with itself; a circumstance that doubtless occasions 

 many to escape from their pitiless foes. Several other 

 weevils, for instance Chlorima nivea and cretacea, resem- 

 ble chalk, and perhaps inhabit a chalky or white soil. 



Many insects also are like pebbles and stones, both 

 rough and polished, and of various colours ; but since 

 this resemblance sometimes results from their attitudes, 

 I shall enlarge upon it under my second head : whether, 

 however, it be merely passive, or combined with action, 

 we may safely regard it as given to enable them to elude 

 the vigilance of their enemies. 



A numerous host of our little animals escape from 

 birds and other assailants by imitating the colour of the 

 plants, or parts of them, which they inhabit; or the twigs 



