The Descent of Man

p. lxxx.) it was supported by various statements;
and Mr. J. Jenner Weir, who keeps a
large number of birds in an aviary, informs me
that he has made many 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
cleansing their beaks, that they were disgusted
by the taste. (34. 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. Mr. Riley has given analogous facts
in the 'Third Annual Report on the Noxious
Insects of Missouri,' 1871, p. 148. Some opposed
cases are, however, given by Dr. Wallace and
M. H. d'Orville; see 'Zoological Record,' 1869, p.
349.) Three conspicuous kinds of caterpillars