17 



less in its larval condition, although having the power of locomotion, 

 it is still more so now, as its position is simply that of a waiting 

 one, generally fixed in one position. The pupas of butterflies are 

 generally attached to the underside of a leaf, those of the moths 

 are either enchsed in cocoons or else buried in the ground. Several 

 of the pupae of butterflies have been found to possess the power of 

 adjusting their colours to those of their surroundings, notably that 

 of the Peacock butterfly {Vanessa lo) which appears in two forms, 

 the common form light grey, and the rarer bright yellowish green. 

 The pupa3 of nearly all the members of this family have brilliant 

 spots of burnished gold on the pupa case. In a series of interesting 

 experiments on the pupa of the Small Tortoiseshell, Mr. Poulton 

 found that this species was very susceptible to surrounding colours. 

 By the use of black surroundings in the caterpillar state, he found 

 that the pupte were, as a rule, extremely dark, with only the smallest 

 trace of the golden spots. On using white surroundings, the very 

 opposite result was produced. The black colouring matter, asa 

 rule, was absent, and there was a great development of the golden 

 spots, so that in many cases the whole surface of thepup^e glittered 

 with a metallic lustre. The pups of A. Iris (Purple Emperor) 

 although of considerable size, is protected by the effect of shadow 

 gained by an arrangement of colour. It spins up on the under 

 side of a sallow leaf. Last year I had a caterpillar sent up from the 

 New Forest, and with the help of Colonel Le Grice, I was fortunate 

 enough to rear it. It was very difficult to distinguish from the leaf, 

 the effect of the colour being to give it a flat appearance. 



The cocoon spun by the caterpillar of the Emperor moth is very 

 interesting. It is pear-shaped, and composed of brownish silk, and 

 is so constructed that the newly emerged moth can easily walk out 

 of the small end without breaking a fibre, while the entry of an 

 enemy from without is impossible. The manner of constructing it 

 is that a number of stiff threads are made to project from the small 

 end of the cocoon, and these converge as they pass outwards, so 

 that the ends are all near together. The other portions of the 

 cocoon are of compact silk, and any insect intruder that ventures to 

 enter by what we may term the open end, is met by a number of 

 spikes, as it were, that repulse it at every attempt. The cocoon of 

 the Puss moth is made of far different material. The caterpillar 

 spins up on the bark of willow trees, and makes a covering for 

 itself out of small pieces of the bark, which it makes so like an 

 ordinary excrescence, that it is very difficult to detect. The con- 

 sistency of the cocoon is so hard that it is difficult to pierce it with 

 a knife. How, then, does the moth escape. As soon as the moth 

 emerges from the pupa case, it ejects a fluid, and softens one end 

 of the cocoon , and thus makes a small hole out of which it slowly 



