496 



HISTORY OF INSECTS. 



Such are the efforts by which these little ! 

 animals prepare for a state of perfection ; but 

 their care is still greater to provide themselves 

 a secure retreat, during this season of their 

 imbecility. It would seem like erecting them- 

 selves a monument, where they were to rest 

 secure, until Nature had called them into a 

 new and more improved existence. For this 

 purpose, some spin themselves a cone or web, 

 in which they lie secure till they have arrived 

 at maturity : others, that cannot spin so copi- 

 ous a covering, suspend themselves by the tail, 

 in some retreat where they are not likely to 

 meet disturbances. Some mix sand with their 



same in progress to maturity. 3. The same at its full 

 growth. 4. Its appearance when about to change into 

 the pupa state. 5. In the act of changing on the follow, 

 ing day. 6. The pupa come forth, the change having 

 been performed in about four minutes. The exuvia of 

 the larva being raised up to the point of suspension, was 

 thrown off, and is represented afterwards at fig. 7. After 

 remaining in the pupa state about twelve days, the per- 

 fect insect begins to appear as at fig. 8. 9 represents the 

 butterfly in the act of escape, and 11 a the pupa case. 

 Tiie following (11 4) is the insect totally extricated, with 



11 b 



the wings folded, collapsed, and humid. 15 is the 

 head of the larva magnified. We have now (12) the in- 

 sect gradually expanding the wings, during which oper- 



ation it voids a sanguineous-looking excrement. And 

 last (fig. 13) the perfect insect (apapileo Urticts) is seen 



with the wings expanded for flight. The whole of the pro- 

 cess from fig. 8. is performed in about seven minutes. 



gummy and moist webs, and thus make them- 

 selves a secure incrustation ; while others, be 

 fore their change, bury themselves in the 

 ground, and thus avoid the numerous dangers 

 that might attend them. One would imagine 

 that they were conscious of the precise time 

 of their continuance in their aurelia state ; 

 since their little sepulchres, with respect to 

 the solidity of the building, are proportioned 

 to such duration. Those that are to lie in 

 that state of existence but a few days, make 

 choice of some tender leaf, which they render 

 still more pliant by diffusing a kind of glue 

 upon it: the leaf thus gradually curls up, and 

 withering as it unfolds, the insect wraps itself 

 within, as in a mantle, till the genial warmth 

 of the sun enables it to struggle for new life, 

 and burst from its confinement. 1 Others, 



1 Leaf -Rolling Caterpillars. The caterpillars which 

 are familiarly termed leaf-rollers, are perfect hermits. 

 Each lives in a cell, which it begins to construct almost 

 immediately after it is hatched ; and the little structure 

 is at once a house which protects the caterpillar from its 

 enemies, and a store of food for its subsistence, while it 

 remains shut up in its prison. But the insect only de- 

 vours the inner folds. The art which these caterpillars 

 exercise, although called into action but once, perhaps, 

 in their lives, is perfect. They accomplish their pur- 

 pose with a mechanical skill, which is remarkable for its 

 simplicity and unerring success. The art of rolling 

 leaves into a secure and immovable cell may not ap- 

 pear very difficult ; nor would it be so if the caterpillars 

 had fingers, or any parts which were equivalent to those 

 delicate and admirable natural instruments with which 

 man accomplishes his most elaborate works. And yet 

 the human fingers could not roll a rocket-case of paper 

 more regularly than the caterpillar rolls his house of 

 leaves. A leaf is not a very easy substance to roll. In 

 some trees it is very brittle. It has also a natural elasti- 

 city, a disposition to spring back if it be bent, which 

 is caused by the continuity of its threads, or nervures. 

 This elasticity is speedily overcome by the ingenuity 

 with which the caterpillar works ; and the leaf is thus 

 retained in its artificial position for many weeks, under 

 every variety of temperature. We will examine, in de- 

 tail, how these little leaf-rollers accomplish their task. 



One of the most common as well as the most simple 

 fabrics constructed by caterpillars, may be discovered du- 

 ring summer on almost every kind of bush and tree. We 

 shall take as examples those which are found on the li- 

 lac, and on the oak. 



A small but very pretty chocolate -coloured moth, abun- 

 dant in every garden, but not readily seen from its fre- 

 quently alighting on the ground which is so nearly of its 

 own colour, deposits its eggs on the leaves of the lilac, 

 and of some other trees, appropriating a leaf to each egg. 

 As soon as the caterpillar is hatched, it begins to secure 

 itself from birds and predatory insects by rolling up the 

 lilac leaf into the form of a gallery, where it may feed in 

 safety. We have repeatedly seen one of them when just 

 escaped from the egg, and only a few lines long, fix se- 

 veral silk threads from one edge of a leaf, to the other, 

 or from the edge to the mid-rib. Then going to the 

 middle of the space, he shortened the threads by bending 

 them with his feet, and consequently pulled the edges of 

 the leaves into a circular form ; and he retained them in 

 that position by glueing down each thread as he short- 

 ened it. In their younger state, these caterpillars sel- 

 dom roll more than a small portion of the leaf; but 

 when farther advanced, they unite the two edges toge- 



