Chap. XI. SUMMAEY ON INSECTS. 417 



Thus the most gaudy colours would be serviceable, and 

 might have been gained by variation and the survival 

 of the most easily-recognised individuals. 



This hypothesis appears at first sight very bold ; but 

 when it was brought before the Entomological Society 32 

 it was supported by various statements ; and Mr. J. 

 Jenner Weir, who keeps a large number of birds in an 

 aviary, has made, as he informs me, numerous trials, 

 and finds no exception to the rule, that all caterpillars 

 of nocturnal and retiring habits with smooth skins, 

 all of a green colour, and all which imitate twigs, are 

 greedily devoured by his birds. The hairy and spinose 

 kinds are invariably rejected, as were four conspicuously- 

 coloured species. When the birds rejected a caterpillar, 

 they plainly shewed, by shaking their heads and cleans 

 ing their beaks, that they were disgusted by the taste. 

 Three conspicuous kinds of caterpillars and moths were 

 also given by Mr. A. Butler to some lizards and frogs, 

 and were rejected ; though other kinds were eagerly 

 eaten. Thus the probable truth of Mr. Wallace's view 

 is confirmed, namely, that certain caterpillars have been 

 made conspicuous for their own good, so as to be easily 

 recognise 1 by their enemies, on nearly the same prin- 

 Ciple that certain poisons are coloured by druggists for 

 the good of man. This view will, it is probable, be 

 hereafter extended to many animals, which are coloured 

 in a conspicuous manner. 



Summary and Concluding Remarks on Insects. — 

 Looking back to the several Orders; we have seen that 

 the sexes often differ in various characters, the meaning 



33 



32 « Proc. Eutomolog. Soc' Dec. 3rd, 1866, p. xlv., and March 4th, 



1867, p. Ixxs. 



33 See Mr. J. Jenner Weir's paper on insects and insectivorous birds, 

 in ' Transact. Ent. Soc." 1869, p. 21 ; also Mr. Butler's paper, ibid p. 27. 



VOL. I. ^ E 



