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LETTER XXL 



MEA^CS BY WHICH IXSECTS DEFEXD THEMSELVES. 



WffTV a country is particularly open to attack, or surrounded by nmnotjos 

 enemies, who from cupidity or hostile feeling are disposed to annoy it, we 

 are usually led to inquire what are its means of defence ? whether natural, 

 or arising from the number, courage, or skill of its inhabitants. The insect 

 tribes constitute such a nation ; with them infinite hosts of enemies wa^e 

 continual war, many of whom derive the whole of their subsistence from 

 them : and amongst their own tribes there are numerous ci^il broils, the 

 strong often preying upon the weak, and the cunning upon the simple : so 

 that unless a watchful Providence (which cares for all its creatures, even 

 the most insignificant) had supplied them with some mode of resistance or 

 escape, this innumerable race must soon be extirpated. That such is the 

 case, it shall be my endeavour in this letter to prove ; in which I shall de- 

 tail to you some of the most remarkable means of defence with which they 

 are provided. For the sake of distinctness I shall consider these under 

 two separate heads, into which, indeed, they naturally divide themselves : — 

 Poiske means of defence, such as are independent of any e5brts of the 

 insect ; and aciire means of defence, such as result from certain efforts of 

 the insect, in the employment of those instincts and instruments with 

 which Providence has fiiriiished it for this purpose. 



I. Tne principal passive means of defence wi:h which insects are provided 

 are derived from their colour and form, by which they either deceive, daz- 

 zle, alarm, or annoy their enemies j or from their substance, involuntary 

 secretions, vitaiity, and numbers- 



They often deceive them by imitating various substances. Sometimes 

 they so exactly resemble the soil which they inhabit, that it must be a 

 practised eye which can distinguish them fit)m it. Thus, one of our 

 scarcest British weevils [Cleonus mbuloius), by its gray colour, spotted 

 with black, so closely imitates the soil, consisting of white sand mrsed 

 with black earth, on which I have always found it, that its chance of escape, 

 even though it be hunted for by the Ij-ncean eye of an entomologist, is not 

 smalL Another insect of the same tribe '^Thi^lac'Jes tcabriculiu), 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 predsely 

 with itself; a circumstance that doubtless occasions many to escape from 

 their pitiless foes. Several other weevils, for instance CAknr.ia rStea and 

 eretacea, resemble chalk, and perhaps inhabit a chalky or white soiL But 

 the most surprising instance of this adaptation of the co'.our of an insect to 

 that of the soil where it resides, is found in some of the Jfanlii tribe sepa- 

 rated by M. Lefebvre under the generic nanie of EreiiTiapkUa, of which he 

 has given so interestins an account. These insects (which he met with in 

 the nvmph state only, in the very midst of the African desert, leading to 

 the Oaaii of Bahryafa, about four days' journey fitim the 2sile, where he 



