INSTINCT OF INSECTS. 



385 



fore noticed — one of those which constantly reside in a sub- 

 cylindrical case — are still more remarkable. This little ca- 

 terpillar feeds upon the elm, the leaves of which serve it at 

 once for food and clothing. It eats the parenchyma or inner 

 pulp, burrowing between the upper and under membranes ; of 

 portions of which 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 mem- 

 branes at the very edge, which with a wise saving of labour 

 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 provided 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 ex- 

 crement, having on one side a nicely joined seam, and the 

 other — that which is commonly applied to its back — com- 

 posed 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. Complicated, 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 ex- 

 posed the little occupant to the day. He expected that it 

 Avould have quitted its mutilated garment and commenced 



VOL. II. c c 



