INTRODUCTORY. 



13 



supported, but yet at some distance from the 

 leaf. The next step it must take is to climb 

 up to the required height. For this purpose 

 it repeats the same ingenious manoeuvre ; 

 making its cast-off skin serve as a sort of 

 ladder, it successively with different segments 

 seizes a higher and a higher portion, until in 

 the end it reaches the summit ; with its tail it 

 feels for the silken threads that are to support 

 it. But how can the tail be fastened to them 1 

 you ask. This difficulty has been provided 

 against by Creative Wisdom. The tail of the 

 chrysalis is furnished with numerous little 

 hooks pointing in different directions, as well 

 adapted to the end in view as the crochets on 

 the caterpillar's claspers, and some of these 

 hooks are sure to fasten themselves upon the 

 silk the moment the tail is thrust amongst 

 it. Our chrysalis has now nearly performed 

 its labours ; it has withdrawn its tail from the 

 slough, climbed up it, and suspended itself 

 from the silken pad, manoeuvres so delicate 

 and perilous that we cannot but admire that 

 an insect which executes them but once in its 

 life should execute them so well ; nor could it, 

 as Reaumur has well and piously observed, 

 'had it not been instructed by a Great Master.' 

 One more exertion remains : it seems to have 

 as great an antipathy to its cast-off skin as one 

 of us should, when newly clothed after a long 

 imprisonment, to the filthy prison garments we 

 had put off. It will not suffer the memento of 

 its former state to remain near it, and is no 

 sooner suspended insecurity than it endeavours 

 to make it fall. For this end it seizes, as it were, 

 with its tail, the threads to which the skin is 

 fastened, and then very rapidly whirls itself 

 round, often not fewer than twenty times. 

 By this means it generally succeeds in break- 

 ing them and the skin falls down. Sometimes, 

 however, the first attempt fails : in that case, 

 after a moment's rest, it makes a second, 

 twirling itself in an opposite direction, and 

 this is rarely unsuccessful. Yet now and 

 then it is forced to repeat its whirling not less 

 than four or five times, and Reaumur has seen 

 instances where the feet of the skin were so 

 firmly hooked that, after many fruitless 

 ellbrte, the chrysalis, as if in despair, gave up 



the task and suffered it to remain. Aftei 

 these exertions it hangs the remainder of it.* 

 existence in this state until the butterfly i.- 

 disclosed." 



This beautiful and graphic account of the 

 conduct of the chrysalis on what may be 

 called its birthday, is extracted from that 

 inexhaustible mine of insect-lore, " Introduc 

 tion to Entomology," by Kirby and Spence. 

 I have, however, verified the facts from 

 actual observation, and only copy the details 

 instead of writing them anew, because the 

 phraseology of their admirable writings is 

 so much better than my own. Still, 

 although I can confirm the statements and 

 attest the accuracy of the description, I 

 am unwilling to accept the reason assigned for 

 some of these extraordinary proceedings. I 

 do not imagine that the whirling movement 

 is performed for the purpose of getting rid of 

 the cast skin : in the first place, because I find 

 that many species elect to retain the skin until 

 the final assumption of the butterfly state, 

 and to preserve it like the rolled-up stocking 

 to which our authors have compared it this 

 is certainly the case in that family which I 

 shall call Satyridce, and probably in many 

 others ; and, in the second place, this whirling 

 is not peculiar to this period of chrysalid 

 existence, and can be induced by irritation 

 whenever an entomologist inclines to make 

 the experiment. 



I must here explain that the chrysalids of 

 insects are of three kinds, called Amorphous 

 (in science Amorpha), when they have no re- 

 semblance to the perfect insect; Necromorph- 

 ous (in science Necromorpha), when they have 

 a striking resemblance to the perfect insect, 

 and exhibit all its limbs swathed as it were 

 in swaddling-clothes ; and Isomorphous (in 

 science Isomorpha), when they resemble the 

 perfect insect in everything but the possession 

 of wings. The amorphous and necromorphous 

 chrysalids can neither eat, fly, nor run ; the 

 isomorphous chrysalids, on the contrary, 

 eat voraciously, leap and run with vigoui', 

 but cannot fly. I/epidoptera, and conse- 

 quently butterflies, belong to the amorphous 

 division. 



