( cxxi ) 



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. 



Considei', 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 Oxfox-d. 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 larvae spun between leaves, 

 and not pupse ; 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 larvae of populdi from some low trees of Populus 

 trcmula which were covered with that species. Captain Robertson had picked 

 otf about 100 larvae 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- 

 ing a 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. 



