178 ANIMAL METAMORPHOSIS. 



one from the other. What can be more unUke than a caterpillar, 

 a crysalis, and a perfect butterfly, the mud-brown aquatic larva of 

 the dragon-fly, and its brilliantly-coloured imago, the rat-tailed 

 maggot, and its adult representative, the hoverer fly, or the pretty 

 little lady-bird, and its ugly, grub-like larva, which has been com- 

 pared to a tiny, six-legged crocodile ? 



The changes differ in degree, but in their most complete form 

 consist of the following series of transformations : — When hatched 

 from the egg, the young insect is always wingless, presenting itself 

 generally under the form of a small, worm-like creature, usually 

 furnished with a certain number of powerful hooked feet, adapted 

 for clinging closely to the surface of the leaves on which it feeds 

 with its powerful masticating jaws. It is technically called a 

 " larva " — popularly, a grub or caterpillar. Its sole object in life 

 now is to eat and grow, which it does rapidly, repeated changes of 

 the skin being necessitated by its continual enlargement. After 

 attaining its full size, it passes into its second stage ; it shrivels up, 

 casts off its skin, takes on a new form, and becomes motionless. 

 It is then called a " nymph," or " pupa." This is a mere transi- 

 tory stage, and in this kind of temporary sepulchre transformation 

 into the perfect insect takes place, and when this is effected, 

 splitting its crysalis-case, it creeps out into the world, drying its 

 body and wings in the sun ; it soars ofl* to sip the flowers, and 

 fulfil the purpose of this third stage of its existence, namely — the 

 reproduction of its species. 



How difterent is the perfect insect from its earlier stages ! 

 The caterpillar-head and powerful horny mandibles have now 

 become useless, and a long, delicate proboscis, with which to suck 

 honey from the flowers, replaces them ; the vigorous feet of the 

 larva are exchanged for long, slender legs, which scarcely rest 

 upon the petals ; the minute eyes, if they still remain on the fore- 

 head, are supplemented by two large compound eyes, which stand 

 out one on each side of the head ; the tiny, stunted antenn?e have 

 become long and delicate ; while from the shoulders spring two 

 pairs of many-tinted wings, which carry it from flower to flower, 

 and help it to escape from the many enemies to which it is 

 exposed. 



