Chap. XI. 
SUMMARY 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 . 33 
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 
recognised 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 
32 ‘Proc. Entomolog. Soc.’ Dec. 3rd, 1866, p. xlv., and March 4th, 
1867, p. Ixxx. 
33 See Mr. J. Jenner Weir’s paper on insects and insectivorous birds, 
in 4 Transact. Ent. Soc,’ 1869, p. 21 ; also Mr. Butler’s paper, ibid. p. 27, 
VOL. I. 2 E 
