452 THE INSECT WORLD. 



continues to do so during the two following years, changing its 

 skin many times during the period. Towards the end of the third 

 year, it changes into a pupa, after having surrounded itself with 

 a shell consolidated with a glutinous froth and some threads of silk. 

 The pupa (Fig. 434) is of a pale russety yellow, with two little 

 points at the extremity of its body ; the elytra and the wings, 

 lying down, cover the legs and the antennae. 



Towards the end of October the perfect insect is already marked 

 out, but it is still soft and weak. It passes the winter in its 

 hiding-place, hardens and becomes coloured at the end of the 

 (winter, and shows itself by degrees on the surface of the ground. 

 In the month of April, three years after its birth, the cockchafer 

 emerges from the earth, and commences its attacks on the leaves 

 of trees. This long duration of the development of the insect 

 explains why we do not see them every year in the same 

 number. When they have once appeared in great quantities, it is 

 not for three years afterwards that we need expect to see their 

 progeny again in proportionate numbers. It is then every three 

 years that we have a cockchafer year, like 1865, but in the inter- 

 mediate years they are never very abundant. For the first 

 year the little larvae do not eat much. They feed then princi- 

 pally on fragments of dung, and on vegetable detritus, and 

 keep together in families. In winter they bury themselves 

 deeply, so as to be secure against frost and floods. Next spring 

 the want of a greater abundance of food forces them to disperse. 

 They then make subterranean galleries in all directions, without, 

 however, going far from the place where they were hatched. 

 They begin attacking the roots which they find within their reach ; 

 the damage they do increasing with their size and the strength of 

 their mandibles. Among roots, they seem to prefer those of the 

 strawberry, and of rose trees ; but they do not despise other vege- 

 tables, and attack legumes and cereals as well as bushes and plants. 

 The ravages which they occasion are sometimes incalculable ; market 

 gardens are sometimes entirely devastated. Fields of lucerne have 

 been seen partially destroyed by them, meadows of great extent 

 lose their pasturage, oat fields die off before they have come to 

 maturity, and many of the ears of corn fall before they are cut- 

 in proportion as they increase in age and in strength, especially 



