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be thus effected, even if insects did possess the requisite brains, 
that is unless we also accord to them the gift of prophecy. 
These are the cases in which instinct prepares for the dangers 
of a struggle at some future time, when the organism which 
manifested the instinct will have changed its form, and become 
incapable of making further changes in the means of protection, 
and indeed as a rule entirely incapable of making any defence. 
Consider, for example, another observation made by Mr. 
Hamm in July 1900, upon the cocoons of Malacosoma neustria 
spun within the leaves of black-currant and apple in his garden 
at Oxford. These he found to be opened by birds, probably 
sparrows, which had pecked a hole in the leaf, thus breaking 
through the cocoon at its thinnest point,* and abstracted the 
chrysalis. 
A still more convincing example is to be found in the 
origin and maintenance of the instincts involved in the con- 
struction of a freely exposed yet admirably concealed cocoon 
on bark. Think of the natural cracks just filled up, of tunnels 
closed flush with the surfaces around, of the resemblance to 
excrescences or ridges which appear perfectly natural upon bark. 
Considering not only the forms but the colours and texture of 
the external surface, we recognize at once that such structures 
are the product of a highly perfected group of instincts. At 
first sight indeed the case seems to prove too much ; for it 
may be thought that such cocoons are so completely hidden 
as to defy the sharpness of any enemy however acute, and 
* The cocoons were exhibited to the Society on March 19, 1902. See 
Proc. Ent. Soc. Lond. 1902, p. xv. 
Mr. W. Holland many years ago showed that birds attack in this 
particular way, but his observation was upon larvze spun between leaves, 
and not pup ; and the latter are specially suited for enforcing the present 
argument. Mr. Holland’s observation is as follows :— 
‘On the 6th of this month [June 1890, near Reading] Captain Robert- 
son and I went to get:some larvie of populeti from some low trees of Populus 
tremula which were covered with that species. Captain Robertson had picked 
off about 100 larve the night before ; but this morning, when we arrived at 
the trees, we found some starlings had also discovered the caterpillars, and 
had gone over the trees systematically from branch to branch, peck- 
inga hole in one side of the spun-together leaves, and drawing out the 
caterpillar, and so nearly had they cleared them all off, that we had much 
trouble to find a dozen. We caught the birds in the act, and although 
they had so nearly finished their feast they were very unwilling to go, and 
loudly objected to our disturbing them,”’—‘‘ Entomologist’s Monthly 
Magazine,” 1890, p. 216, 
