IXTRODUCTION. 21 



the resplendent Cephas aiul Bnthnus (popularly known as Diamond 

 Beetles) of Brazil; and the bejewelled Cratopus, peculiar to the 

 islands of the Indian Ocean. 



'The comparative paucity of conspicuously marked species pro- 

 bably indiL-ates a general hick of qualities distasteful to those 

 animals which would be likely to prey upon them, such as an 

 unpleasant taste or smell, the possession of which it Avould be 

 profitable to advertise by means of conspicuous coloration. The 

 schemes of colouring are for the most part undoubtedly j)'"0: 

 cryptic, that is to say, they harmonise with the natural sui-rouud- 

 iugs of the insect so as to render it inconspicuous ; and this is 

 probably true of the metallic green scaling which so frequently 

 manifests itself among the small leaf-eating species of many 

 different genera of Abelognathi, but which, for some reasoii 

 that is not obvious, is extremely rare among the species with a 

 long rostrum that have similar habits. 



But though they may be deficient in active deterrents for their 

 enemies, the weevils have very widely adopted an effective passive 

 means of defence, namely, extreme hardness, not infrequently 

 accompanied by the presence of sharp spines on the thorax and 

 elytra which nuist render them uncomfortable morsels for swallow- 

 ing whole. This method of protection is naturally best developed 

 in the larger wingless terrestrial forms. The species of Pacliy- 

 rrhjncJius, referred to above, are certainly extremely hard and may 

 possess other deterrent qualities, and there seems to be some 

 reason for supposing that their striking patterns have a warning 

 significance, for they are mimicked Avith extraordinary accuracy 

 by certain Longicorus of the genus BoUops. Similarly, in other 

 parts of the world various large terrestrial weevils are closely 

 resembled by wingless Lougicorns having similar habits. These 

 are the only recorded cases in «hich we may reasonably assume 

 that weevils have served as models for other insects. On the 

 other hand, no case has yet been demonstrated of a weevil 

 mimicking another insect, and this is the more remarkable when 

 we consider what vast luimbers of CuucT:LIO^'IU.E there are and 

 what extremely varied, and sometimes fantastic, forms they have 

 assumed. 



Most weevils are somewhat slow in their movements, and it 

 is only among certain groups of the Zyuopin^e with rather short 

 elytra and slender legs that we find any species that are really 

 active ; these insects, when disturbed, are capable of taking to 

 flight quite as rapidly as tiger-beetles of the genus Cicindela. 

 With most species the unfolding of the wings is a rather laborious 

 process, and no doubt it is mainly on this account that they have 

 so widely adopted the disconcerting habit of dropping suddenly 

 from their food-plant into the herbage beneath on the slightest 

 sign of danger. The protective value of this method of escape 

 is further enhanced by a kind of behaviour that is more widely 

 prevalent in this family than among other beetles, namely, the 

 death-feigning instinct. This is especially well marked in those 



