1648 The Zoologist— A pkil, 1869. 



Mr. A. G. Butler read a paper " On some Caterpillars which are unpalataWe to 

 their Enemies." 



Mr. Weir's experiments were suggested by the remarks of Mr. Alfred R. Wallace, 

 reported in Proo. Eut. Soc. 1867, p. Ixxx. : the conclusions at which he arrived were, 

 that, as a rule, hairy and si)inous larvae were rejected by birds (unless the cuckoo were 

 au exception) ; but he doubted whether the mechanical difficulty of swallowing them 

 was the cause of their rtjection, and rather thought that the huiis were the con- 

 comitant of a disagreeable quality of which they acted as an indicator; that bright 

 and gaily-coloured larva were, as a rule, refused ; but that smooth larvae of a greenish 

 or dull brown colour, such as are for the most part nocturnal in their habits, and those 

 which simulate the leaves or twigs of trees upon which they live, were eaten with 

 avidity. 



Mr. Butler's observations were on the consumption or rtjection of larviE by lizards, 

 frogs and spiders; both lizards and frogs would eat hairy larva;; and even the stings 

 of bees had no deterrent effect upon a lizard. 



These two papers led to a prolonged conversation, in which the President, 

 Mr. Home, Mr. A. R. Wallace, Mr. Butler, Mr. M'Luchlan and Dr. Wallace, took 

 part. 



Mr. Home said that in India lizards were almost omnivorous, and ate bees with 

 avidity ; a friend of his, Colonel Ramsay, had hives of Aphis dorsata placed near some 

 stone wails or terraces, which were a favourite resort of lizards; they would come to 

 the mouths of the hives, lie in wait for the bees, and take them, sting and all. Larvae 

 of all sorts, smooth or hairy, dull or bright, were eaten by lizards ; but scorpions were 

 rejected ; bears, however, would eat scorpions, and he had seen bears turn over stones 

 in search of scorpions, and eat them regardless of their stings. He had noticed that 

 a common Indian species of Carahus, and all the blister-beetles, seemed to be free 

 from attacks of any animal. 



Dr. Wallace said that the larvae of Borabyx Cynthia, which were both gaily 

 coloured and covered with tubercles, were eaten by cuckoos, robins and tomtits: the 

 two latter made holes in the skin and took out the inside, whilst the cuckoos swallowed 

 the larvae whole. 



Mr. Alfred R. Wallace was pleased to find that the observations of Mr. Weir went 

 so far to sufiport the theory which, reasoning entirely from the analogy of what had 

 been observed iu the Heliconiida;, he had ventured to suggest in answer to a question 

 of Mr. Darwin's. He thought there was now a solid foundation of fact for the hypo- 

 thesis that the bright colour of larvae was protective, and was (as it were) a flag hung 

 out to warn off their enemies. Doubtless every detail either of form or colour had its 

 object and bearing upon the history of the creature. It was not necessary that the law 

 should be absolute or the rule universal ; he did not expect to find, on the contrary he 

 should have been surprised if it had been found, that all bri>;htly coloured larvce were 

 peculiarly protected, or that the bright colour oi mny particular larva protected it from 

 all enemies ; if it thereby obtained protection from a single enemy, if it was left 

 exposed to the attack of but one enemy less than its neighbours, to that extent at 

 least the colour gave it au advantage ; the theory of protective warning supplied the 

 reason for, and afforded a rational explanation of, the gay colouring, which iu the 

 case of larvae could not be accounted for by sexual selection. — /. W. D. 



