392 THE INFLITENCB OF LIVING SUEROnNDINQS. 



known as the coral snake — by Homalocranium semicinctum ; 

 Maps lemniscatiis, of which the bite is said to be absolutely 

 fatal, hy Pliocerus elapoides; and all again are imitated by yarious 

 species of the quite harmless genus Oxyrhopus, which live asso- 

 ciated with the poisonous kinds. The two cases, communicated 

 by Wallace, of birds which mimic other birds, seem certainly to 

 come under this head ; the Tropidorhynchus, dreaded for its 

 strength, is mimicked by the helpless Mimeta, &ndAecipitergale- 

 atus, ahird of prey which feeds on other birds, exactly resembles 

 the insectivorous vulture Harpagoa, wherever the two species 

 occur together. But the only instance adduced by Wallace of 

 mimicry among quadi upeds — the resemblance of an insectivorous 

 Cladohates to the squirrels (rodents) — seems to me, on the other 

 hand, to be included with less reason in this class of resem- 

 blances. The assumption seems to me without foundation that 

 the squirrels are harmless creatures and cannot alarm the 

 insects around them by their movements, so that the Insectivora 

 which resemble them easily capture theii' food. The European 

 squirrel, at any rate, is omnivorous, as are many rodents ; and 

 granting even that they never eat insects, it does not appear to 

 me to be by any means established by observation that insects 

 would remain motionless when the squirrel, as he leaps from 

 bongh to bough, shakes every leaf and twig. 



Thus, omitting this case of the imitation of a squiixel by an 

 insectivorous animal, the cases of mimicry that ' are here men- 

 tioned seem to be well established on the whole. In each case 

 it can be shown that the mimicked spscies is in some way very 

 effectually protected by an offensive smell, weapons of some 

 kind, a hard skin, a powerful frame, &c., while the mimicking 

 form is, without exception, weak and devoid of defence, so as to 

 be greatly in need of protection. It can, moreover, be proved 

 that in many cases, if not in all, the mimicking species live 

 associated with those they resemble. 



From the facts thus established by observation, Bates and 

 Wallace argue as follows. They show that all mimicking 

 forms have acquu'ed, by their disguise, an imdeniable advan- 

 tage in the struggle for existence over those less well equipped, 

 since, in consequence of the disguise, either they escape 



