THE TRESEnVATION OF INSECTS. 77 



undergo three or four; Heterocerata generally four, except some hairy 

 species in which seven or eight have been counted. 



The skin of the caterpillar is a kind of epidermoid membrane which 

 has only a limited power of extension, and it is easy to conceive that 

 the animal can not remain in this rigid envelope during the whole period 

 of its growth. The resulting phenomenon has a very close analogy 

 with the moulting of higher animals, with this exception, that in the 

 latter the hair does not fall off, whilst in caterpillars it disappears 

 with the general envelope. The cause of this difference is, that in the 

 one case it is adherent to the tissue of the skin and passes through 

 the epidermis, but in the other where that tissue does not exist at all, it 

 is placed immediately upon the external (tegumentary) membrane; thus 

 each moulting of a caterpillar is so complete that it may be taken for 

 the insect itself. This does not extend to the palpi, antennae, and max- 

 illae, which are not found there complete. 



The caterpillar, informed by a peculiar instinct that its time of moult- 

 ing has arrived, prepares itself by dieting for the endurance of that crisis. 

 As this approaches, the colors become dim or livid, the old skin shrivels 

 and splits open upon the back at the second or third ring. The cater- 

 pillar in order to get out of this envelope, first disengages the forepart 

 ■<5f its body and then the hinderpart. This operation, so troublesome, 

 is sometimes finished in less than a minute, hidividuals that have just 

 moulted are easily distinguished by the brightness of their colors, and 

 sometimes the design is different from what it \vas before. The number 

 of moultings differs in the same species, though in a wild state it may 

 be more regular, but in those covered with hair, when fed in captivity, 

 the number of moultings may be increased or diminished by a more or 

 less abundant supply of food. 



THE PROVIDEiVCE OF GOD IN THE PRE-SERVATION OF INSECTS. 



The Providence of God is wonderfully displayed in the preservation 

 of creatures apparently the least important in the household of nature. 

 It extends to the minutest animals that spend their ephemeral existence 

 on the earth. Not only are the living preserved until they have per- 

 formed their destined functions, but extraordinary arrangements are 

 made for the perpetuity of the species, so that it is likely very few kinds 

 of animals, of which history gives usany account, have become totally 

 extinct. 



In no class of animals is this perpetuating Providence more remark- 

 ably exhibited than in Insects. They, like all other animals, arc objects 



