80 



HECREATIYE SCIENCE. 



them, and those who wish to see the wonder- 

 ful transformation of this interesting tribe of 

 insects, should take some of the largest cater- 

 pillars that they can find feeding upon the 

 leaves of the nettle, and place them in a cage 

 made for the purpose, or an ordinary bird- 

 cage, covered with thin muslin or lace, to 

 prevent their escape. Then feed them with 

 the fresh leaves of the nettle until they have 

 arrived at maturity; after which they become 

 listless, and soon change into the piipa state, 

 and thus remain dormant for a time. They 

 then burst the hard case which covers them, 

 and the perfect butterfly comes forth decked 

 in all its brilliant colours, and is soon ready 

 for flight, and no one, however much he may 

 have disliked the unattractive caterpillar, will 

 now fail to admire the perfect insect clothed 

 in its beautifully-coloured and exquisitely- 

 arranged minute scale-like feathers. The 

 butterfly, soon after it becomes fully deve- 

 loped, deposits a considerable number of 

 small roundish eggs, and always places them 

 on or near the plant suited for the young 

 caterpillar which each egg contains, and in the 

 course of a short time, by the aid of the heat of 

 the sun, breaks its delicate shell. Thus, with- 

 out much difficulty or trouble, may be ob- 

 served all the remarkable transformations 

 which the progeny of the butterfly undergoes. 

 Let us, however, inquire more particularly into 

 the changes which this insect passes through 

 in the different stages of its existence, and in 

 so doing, we shall obtain a general idea of 

 what takes place in the metamorphosis of the 

 whole tribe of butterflies and moths. 



If the delicate little eggs which the but- 

 terfly has deposited are collected, it will be 

 found that about a hundred of them do not 

 weigh more than a grain, consequently, when 

 the little caterpillar is liberated from its 

 shell, it is a very minute, delicate, little crea- 

 ture; it soon, however, increases in size, 

 so that in a few days its body is so much 

 enlarged that its outer coat, or skin, is unable 

 to contain it ; consequently, this is cast off". 



and the body is then seen to have increased 

 in size. Soon after this change of its coat it 

 begins again to feed upon the leaves of the 

 nettle with greater avidity, and in a few more 

 days it is so much grown as to again require 

 a new and larger skin. It goes through this 

 change five times, and each time it has become 

 considerably larger. It wiU be observed that 

 a few hours before each time that the lava is 

 ready to cast its skin, that it ceases to eat, 

 and it usually attaches itself on the under 

 side of the leaf of the plant, and there awaits 

 its change. It has the appearance of being 

 uneasy, and the whole body is wrinkled and 

 contracted in length, the skin becomes dry 

 and shrivelled, and is gradually separated 

 from the new, but yet delicate, skin beneath 

 it. At length, after some powerful efforts of 

 the larva, the old skin is cracked, and it gra- 

 dually presses itself through the opening. 

 It then appears for some time very delicate 

 and ill-proportioned, from the head being 

 much larger in proportion to the body, but 

 it will be seen that the head does not increase 

 in size with the body, but remains the same 

 until the next change of the skin. In a few 

 hours after this change has taken place, the 

 caterpillar begins again to feed voraciously, 

 but more especially so after the last skin has 

 been changed, during which period its growth 

 is much more rapid than at any previous 

 time. When the caterpillar has attained its 

 fuU growth it ceases to eat, becomes very 

 restless, and is diminished in size and weight ; 

 it completely evacuates the contents of the 

 alimentary canal, and then suspends itself by 

 its hinder legs, and attaches itself by a silken 

 web upon a branch, or other convenient object, 

 with its head hanging downwards, and thus 

 it awaits its next and important transforma- 

 tion, which takes place in from ten to twenty 

 hours. During this time the body becomes 

 contracted, and looks dry and shrivelled ; the 

 four segments nearest the head become larger 

 than the others, which are repeatedly con- 

 tracted and expanded; at length the skin 



