ON ENTOMOLOGY. 13 



preliminary, for it has still to throw off its skin together with the 

 hooks by which it is suspended, and this without losing its hold. The 

 old skin is rent by the forcible bending round of the upper part of the 

 body, which pushes through the angular projections of the Chrysalis, a 

 tedious and probably a painful operation, in which it is often engaged 

 the greater part of a day, and sometimes two according to its strength. 

 When the first rent is made, however, the included Chrysalis soon wedges 

 itself through the breach, the lower portion swelling out greatly more 

 than the upper, so as to form an inverted but somewhat irregular cone. 

 The included insect continuing its laborious exertions, by successively 

 contracting and dilating the rings of its body, pushes off the now rent 

 skin by degrees from the head towards the tail, as one w r ould roll 

 down a stocking from the leg. There are two circumstances worthy of 

 notice in this process, the position of the insect in hanging with its head 

 downwards, throws a greater portion of the fluids of the body towards 

 the head, by means of their weight, which swell out the part that splits, 

 and also pushes back the old skin, while the sloughing skin is prevented 

 from resiliating by a series of pegs, which act like the toothed rack of 

 a sluice gate. The old skin being by these means pushed towards the 

 tail, is of course compressed into several folds, which in some degree 

 prevent the extension of the rent, and serve to keep the Chrysalis from 

 falling, for being now detached from the skin, it lias no hold upon the 

 meshes of the silk button, and is in fact at some distance from it. This 

 then is the part of the process where the nicety of the mechanism is 

 most worthy of admiration, for the hooks by which the insect is in the 

 first instance suspended from the meshes of the silk, are sloughed 

 off together with the skin, the grasp of whose folds becomes then the 

 only support of the Chrysalis. 13ut this Chrysalis now deprived of feet, 

 and some distance from the suspensary cordage of silk, has still to 

 reach this, fix itself there, and cast off the sloughed skin altogether. 

 This operation causes, says Bonnet, a spectator to tremble for the con- 

 sequences, for every movement seems to render its fall almost certain. 

 It is, however, provided with means which answer the same purpose as 

 hands to enable it to climb, it can elongate and contract at pleasure the 

 rings of its body j it accordingly with two contiguous rings lays hold, 

 as with a pair of pincers, of the portion of the sloughed skin nearest the 

 head, and elongating the rings beyond this seizes upon a more distant 

 portion, while it lets go the first; repeating the process several times 

 it arrives at the silk button. The Caterpillar is solitary, spinous, and 

 greenish, with a yellowish lateral line ; at the end of July changes into 

 the pupa ; in fourteen days after becoming a Chrysalis, the Butterfly 

 appears. 



The VANESSA lo (Peacock Butterfly) appears in spring, and the middle 

 of July, till late in autumn ; wings above purplish or reddish brown, 

 with a large eye-like spot near the tip of the first, and towards the 

 margin of the second pair, underneath brown, marbled, banded, and 



