602 ARTICULATES. 



In the larval state, insects eat most voraciously, indeed, their 

 entire energy seems to center in the eating process. Their 

 growth is great, and often rapid. The comparative weight of 

 that remarkable insect, the Great Moth, Cossus ligniperda, to 

 that of the young one that has just crept out of the egg is, as 

 7*2,000 to 1, an increase of seventy-two thousand times! This 

 insect occupies three years in attaining to its perfect state. The 

 Maggots of Flesh-Flies are said to increase in weight two hun- 

 dred times in twenty- four hours. Caterpillars, in the same time, 

 consume three times their weight of food. 



Larvae are subject to moultings, or changes of the skin ; the 

 number varying with the species. This moulting is most strik- 

 ingly exhibited in the Silk- worm, Bombyx mori, which casts its 

 outer skin five times in a month. While undergoing this pro- 

 cess, the larva does not eat, but it absorbs the fat beneath the 

 outer skin, which favors casting it off. 



The larval state is the one in which insects continue the 

 longest, varying, however, in duration, from hours to months 

 and years. 



The Caterpillars of several Butterflies and Moths, live in large 

 societies, in habitations or tents, sometimes of a pyramidal 

 form, and which are constructed by their united skill. 



When the worm has fixed itself in some suitable and secure 

 retreat, the pupa is formed, and encased in the last skin, which, 

 in two winged insects, becomes more rigid ; or else a new and 

 beautiful case is made, a robe of silk, impervious to water, 

 being laboriously woven from a single thread, which is formed 

 and spun from the juices of the body, impressively illustrating 

 the instinctive power of the insect as related to its successive 

 developments. 



The name of the third state, pupa, (child or doll,) refers to the 

 swathed appearance of most insects during its continuance, it 

 resembling, in miniature, a child trussed up in swaddling 

 clothes. 



This state has two modifications. (1) That of those which, 

 in general form, resemble their larvae; (2) That of those which 

 are entirely unlike their larvae. Of the first kind are the He- 

 miptera, &c., which have the pupa somewhat incomplete, and 

 possess rudimental wings; also those which have an incomplete 

 pupa, and are also without wings, as Lice, Pediculus, which, 

 and the Spring-tails, Podura, together with some other wingless 

 insects, undergo no metamorphosis, corning forth from the egg, 

 almost in the condition in which they remain all their lives. 



