250 NATURAL HISTORY. [cH. XVII. 



full size being nearly twice as large as when first 

 deposited. We, however, suggest, that the growth 

 of the enclosed larva is attributable rather to fluid 

 nutriment contained vt^ithin the egg than to any im- 

 bibition of fresh matter. The subject is, neverthe- 

 less, highly worthy of attention. 



The larvae which are hatched from these eggs 

 are often to be noticed in great quantities, and are 

 the most destructive to the vegetable vv^orld of any 

 of the insects in the order to which they belong. 

 The gooseberry, currant, raspberry, cherry, rose, 

 &c. being often entirely stripped of leaves by vari- 

 ous species ; this is especially the case when sev- 

 eral females, each of which deposites a very consid- 

 erable number of eggs, have selected the same tree. 

 When this takes place, and the leaves are, in con- 

 sequence, entirely consumed, the appearance of 

 these grubs is, of course, attributed to blight : the 

 willow and birch are no less subject to their attacks, 

 and even the wheat and barley are often seriously 

 injured by them. 



These larvas greatly resemble in form the cater- 

 pillars of butterflies and moths, being of a cylindri- 

 cal form, with a scaly head, furnished with very 

 powerful jaws, and having three pairs of scaly legs 

 attached to the flrst three rings of the body, and 

 several other pairs of fleshy membranous legs 

 (varying in number in the different species) attach- 

 ed to the hinder segments of the body. They may, 

 however, be readily distinguished from the cater- 

 pillars of the Lepidoptera, by the peculiar attitude 

 which they assume when disturbed, coiling them- 

 selves up in a spiral form, with the head iirthe cen- 

 tre of the coil, and lying motionless upon their 

 sides. When feeding upon a leaf, they commence 

 their attack on it upon that side which they hold 

 between their six forelegs ; they are extremely vo- 

 racious, feeding very fast, and without intermission. 

 The larvas of many of the smaller species live 



