BRITISH INSECTS 



991 



natural selection. It 

 has been argued, how- 

 ever, that though the 

 individual conspic- 

 uous insect may be 

 martyred on occasion 

 by reason of his 

 conspicuousness, his 

 martyrdom must be 

 regarded as highly 

 advantageous to his 

 relations. A young 

 bird or lizard, for 

 example, may, and 

 probably does, in the 

 callow stage sample 

 Wasps and yellow- 

 and-black Caterpil- 

 lars. The sting of the 

 former, however, and 

 the nauseous taste of 

 the latter, linger in 

 his memory, and four 

 or five experiments 

 determine him to 

 avoid yellow - and - 

 black victuals alto- 

 gether. Were Wasps 

 and, say. Cinnabar 

 Caterpillars protec- 

 tively coloured, the 

 young bird or lizard 

 would, for the want 

 of any means of dis- 

 t i n g u i s h i n g them 

 from wholesome food, 

 continue to be stung 

 and to be made sick, 

 both to his own disad- 

 vantage and to the disadvantage of Wasps 

 and of Cinnabar Caterpillars generally. 

 Though black in combination with red- 

 brown, yellow, or orange is the most 

 obvious form of " warning " coloration, 

 it must be remembered that the theoreti- 

 cal pui"pose of " warning " colours is a 

 conspicuous advertisement of the owner's 

 disagreeable qualities, and that this 

 advertisement may be effected by any 

 colour, or by any form, which is markedly 

 dissimilar from, and so markedly in 

 contrast with, its normal surroundings. 

 The whiteness, therefore, of Wiiite 

 Butterflies, the metallic patches on many 

 chrysalides, the aggressive hairiness of 

 "Woolly Bears," and the devil-may-care 



TWO REMARKABLE DEFENSIVE ATTITUDES 

 ADOPTED BY BRITISH CATERPILLARS. 



1 The Puss Moth Caterpillar extruding filaments 

 from the projections on the hind part of his 

 body, and telescoping his front segments to 

 show his eye-markings. 



2. The Lobster Moth Caterpillar, mimicking spider. 



publicity of gregari- 

 ous Caterpillars, may 

 each and all be 

 danger signals. 



It is a matter of 

 some difficulty for 

 the field naturalist 

 to reconcile his own 

 experience with the 

 ex])erimental proofs 

 of the warning cohjur 

 theory which have 

 been conducted in 

 the vivarium. He 

 has seen Ichneumon 

 Flies attack bril- 

 liantly coloured 

 Caterpillars in the 

 open ; he has seen 

 birds and lizards eat 

 black and yellow in- 

 sects, not with " evi- 

 dent signs of disgust," 

 but with evident signs 

 of satisfaction. He 

 knows that the most 

 flamboyant combina- 

 tions of colour vanish 

 amid suitable sur- 

 roundings ; that they 

 are on occasion at 

 least as protective as 

 sombre colours ; and 

 that their protective 

 character is due to 

 their brilliance. Ex- 

 perience has taught 

 him that in his own 

 quest for food he 

 conforms to definite conventions — he 

 would have to be extremely hungry, 

 for example, before he ate a sandwich 

 which he found lying in the road — and 

 he is inclined to suppose that insect ivores 

 among the lower orders may perhaps 

 have conventions of their own, which 

 make them diffident of eating anything, no 

 matter what its colour is, which is not 

 in such a situation as their food is usually 

 found in, or behaving in sucli a way as 

 their food usually behaves. This, in his 

 judgment, accounts sufliciently for the 

 fact that birds who arc accustomed to 

 Imnt for caterpillars under lea\'es. look 

 askance at an assemblage of Cinnabar 

 Caterpillars naked and unashamed on 



