40 ELEMENTS OV ENTOMOLOGY. 



Of the LAlTV^A, or CutcrpiUar state. All caterpillars are hatched 

 from the egg, and when they first proceed from it are generally small 

 and feeble, hut grow in strength as they increase in size. The body of 

 the caterpillar consists of twelve rings ; the head is connected with the 

 first, and is hard and crustaceous. No caterpillar of the moth or butterfly 

 has less than eight, or more than sixteen, feet; those which have more 

 than sixteen belong to some other order of insects. The six anterior 

 feet, or those next the head, are hard and scaly, pointed and fixed to 

 the first three rings of the body, and are in number and texture the 

 same in all Lepidopterous larvae. The posterior feet are soi't, flexible, or 

 membranaceous ; they vary both in figure and nvnnber, and are observa- 

 ble only in the caterpillar state, the perfect insect having only six feet, 

 the rudiments of which are the six anterior scaly feetbeibre mentioned. 

 These spurious feet are either smooth or hairy, soft to the touch, or 

 hard like shagreen. On each side of the body are nine small oval 

 apertures, which are the spiracles or organs of respiration. 



The caterpillar, whose life is one continued succession of changes, 

 often moults its skinbefore it attains its full growth. These changes are 

 the more singular, because when it moults it is not simply the skin that 

 is changed ; ibr we find in the exuviae the jaws, and all the exterior parts, 

 both scaly and membranaceous. 



. The change in the caterpillar is effected by the creature's withdrawing 

 itself from the outer skin as from a sheath, when it finds itself ijicom- 

 moded from being confined within a narrow compass. But to accomplish 

 this change is the work of some labour and time. Tho^e caterpillars 

 which live in society, and have a nest or habitation, retire there to change 

 their skin, fixing the hooks of the feet, during the operation, firmly in 

 the web of their nest. Some of the solitary species spin at this time a 

 slender web, to which they affix themselves. A day or two before the 

 critical moment approaches, the insect ceases to eat, and loses its usual 

 activity ; in proportion as the time of its change approaches, the colour 

 of the caterpillar delines in vigour, the skin hardens and becomes 

 withered, and is soon incapable of receiving those circulating juices by 

 which it was heretofore nourished and supported. The insect is now 

 seen at intervals with its back elevated, or with the body stretched to 

 the utmost extent: sometimes raising its head, moving it from one side 

 to another, and then letting it fall again. Near the change the second 

 and third rings are seen considerably swollen. By these internal ef- 

 forts the old parts are stretched and distended as much as possilile, an 

 operation attended with difficulty, as the new parts are all weak and 

 tender. However, by repeated exertions, all the vessels which con- 

 veyed nourishment to the exterior skin are disengaged, and cease to 

 act, and a slit is made on the back, generally beginning at the second 

 or third ring. The new skin may now be just perceived, being distin- 

 guished by its freshness and brightness of colour. The caterpillar then 



