CATERPILLARS. 167 



ieaf-rolling insects find that the larger nervures of 

 the leaves are so strong as to prevent them from 

 bending, they ^' weaken it by gnawing it here and 

 there half through." We have never observed the 

 circumstance, though we have witnessed the process 

 in some hundreds of instances; and we doubt the 

 statement, from the careful survey which the insect 

 makes of the capabilities of the leaf before the oper- 

 ation is begun. If she found upon examination that 

 a leaf would not bend, she would reject it, as we have 

 often seen happen, and pass to another.* 



A species of leaf-roller, of the most diminutive 

 size, merits particular mention, although it is not 

 remarkable in colour or figure. It is without hair, 

 of a greenish white, and has all the vivacity of the 

 other leaf-rollers. Sorrel is the plant on which it 

 feeds; and the manner in which it rolls a portion of 

 the leaf is very ingenious. 



The structure which it contrives is a sort of conical 

 pyramid, composed of five or six folds lapped round 

 each other. From the position of this little cone the 

 caterpillar has other labours to perform, beside that 

 of rolling the leaf It first cuts across the leaf, its 

 teeth acting as a pair of scissors; but it does not 

 entirely detach this segment. It rolls it up very gra- 

 dually, by attaching threads of silk to the plane sur- 

 face of the leaf, as we have before seen; and then, 

 having cut in a different direction, sets the cone 

 upright, by weaving other threads, attached to the 

 centre of the roll and the plane of the leaf, upon 

 which it throws the weight of its body. This, it 

 will be readily seen, is a somewhat complicated effort 

 of mechanical skill. It has been minutely described 

 by M. Reaumur; but the following representation 



♦ J. R. 



