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V. A few words respecting Insects and their Natured Enemies. 
By Arthur G. Butler, Ph.D., F.L.S., F.Z.S., F.E.S., 
M.B.O.U. 
[Read March 2nd, 1910.] 
I WAS much interested in the perusal of Mr, H. Eltring- 
ham’s account of his experiments on the edibility of 
Lepidopterous larvae by lizards; for, although it is now 
many years since I made experiments with these charming 
reptiles, I have for a long time—since 1883 in fact—kept 
a large family of living birds, with which I have frequently 
experimented. 
That a bizarre appearance or startling colours afford 
considerable protection to certain caterpillars, in the case 
of all birds not intimately familiar with them, is an un¬ 
doubted fact; though in the case of birds which see them 
daily they afford the caterpillars no protection whatever, 
but rather serve as an attraction. Thus many birds which 
naturally seek their food upon the ground will not look at 
or will be nervous of seizing the caterpillar of Cerura 
rinula, w'hereas those birds (like the Tits) which seek for 
much of their insect-food among the branches of trees 
seize it and tear it to pieces without a moment’s hesitation. 
Bright colours, and especially metallic colours, are very 
attractive to birds; consequently the golden chrysalides of 
some of the Vanessae and the more metallic Pkisiae, such 
as P. chrysitis, are eagerly devoured by many birds; a fact 
w'hich used to be doubted, on the supposition that a bird 
would mistake the colouring for actual metal. That birds 
reason I have no doubt; but, when in search of food, they 
test an object first, and reason about it afterwards when 
they have found it unpleasant. 
Touching so-called warning colours I am very sceptical; 
a bird has a great appreciation of form and outline, and, 
however coloured, rarely attempts to eat a really nauseous 
insect after the first trial; though in the case of some 
moderately unpleasant caterpillars, rejected at first per¬ 
haps because their flavour w’as unusual, I have known a 
TRANS. ENT. SOC. LOND. 1910. —PART II. (JUNE) 
