574 INSTINCT OF INSECTS. 



cut out, and properly sewed together, it forms its case. Its usual plan is 

 to insinuate itself between the epidermal membranes of the leaf, close to 

 one of the edges. Parallel with this it excavates a cavity of suitable 

 form and dimensions, gnawing the pulp even out of every projection of 

 the serratures, but carefully avoiding to separate the membranes at the 

 very edge, which with a wise saving of labor it intends should form one 

 of the seams of its coat ; and as the little miner is not embarrassed with 

 the removal of the excavated materials, which it swallows as it proceeds, 

 a cavity sufficiently large is but the work of a few hours. It then lines 

 it with silk, at the same time pushing it into a more cylindrical shape; and 

 lastly, cutting it off at the two ends and inner side, it sews up the latter 

 with such nicety that the suture is scarcely discoverable ; and is now pro- 

 vided with a case or coat exactly fitting its body, open at the two ends, 

 by one of which it feeds, and by the other discharges its excrement, 

 having on one side a nicely joined seam, and the other — that which is 

 commonly applied to its back — composed of the natural marginal junction 

 of the membranes of the leaf. 



Such are the ordinary operations of this insect, which, — when it is 

 considered that the case is rather fusiform than cylindrical ; that the end 

 through which it eats is circular, and the other curiously three-cornered 

 like a cocked hat ; and that consequently its cloth requires to be very 

 irregularly and artfully cut to be accommodated to such a figure, — it must 

 be admitted, are the result of an instinct of no very simple kind. Com- 

 plicated, however, as these manoeuvres seem, our ingenious workman 

 is not confined to them. By way of putting its resources to the test, 

 Reaumur cut off the serrated edge from the nearly finished coat of one of 

 them, and exposed the little occupant to the day. He expected that it 

 would have quitted its mutilated garment and commenced another; and 

 so it certainly would, had it been guided by an invariable instinct. But 

 he calculated erroneously. Like one of its brother tailors of the biped 

 race, it knew how " to cut its coat according to its cloth," and immediately 

 setting about repairing the injury sewed up the rent. Nor was tliis all. 

 The scissars having cut off one of the projections intended to enter into 

 the construction of the triangular end of its case, it entirely changed the 

 original plan, and made that end the head which had been first designed 

 for the tail. 



On another occasion Reaumur observed one of these larvas to cut out 

 its coat from the very centre of a leaf, where it is obvious a series of 

 operations wholly different must be adopted, the two membranes compos- 

 ing it necessarily requiring to be cut and sewed on two sides instead of on 

 one only. But what was most striking in this new procedure was the 

 alteration which the caterpillar made in the period of sewing up its gar- 

 ment. When these larvaj cut out their case from the edge of a leaf, they 

 seem aware that if they were to detach it entirely from the inner side 

 before the process of sewing, liniag, &;c. is completed, having no support 

 on the exterior edge, it would be liable to fall down ; at the time they 

 could not sew together the membranes composing it at the inner side, 

 without cutting them in part from the leaf. While, therefore, they divide 

 the major part of their inner side from the leaf, they artfiilly leave thera 

 attached to it by one of the large nerves at each end ; and these supports 



