INSECTS 



395 



rolled so as to form, each one, a little funnel. . . . An inspection 

 of one of these funnels will show that it is very carefully con- 

 structed. The whole of a leaf is not used in the formation of a 

 funnel, cuts being made across the leaf in suitable directions. The 

 beetle, standing on a leaf, as shown in the figure, proceeds to cut 

 with its mandibles an incision shaped like an erect S, commencing 

 at a certain part of the circumference, and ending at the midrib of 

 the leaf; the beetle then goes to the other side of the midrib, and 

 continues its incision so as to form another S-like curve consider- 

 ably different from the first, being prostrate and less abrupt. 



Fig. 9x6. 



-Birch- Weevil {Rhynchites betula). a, Adult Weevil (actual size indicated byline to left), 

 constructing egg-case, c, Completed egg-case. 



B, Weevil 



Thus the blade of the leaf is divided into two halves by certain 

 curved incisions, the midrib remaining intact. The little funnel- 

 twister now commences to roll up the leaf to form the funnel ; and 

 this part of the work is greatly facilitated by the shape of the 

 incisions. Going back to the spot where it commenced work, by 

 the aid of its legs it rolls one side of the leaf round an ideal axis, 

 somewhat on the same plan as that adopted by a grocer in forming 

 a paper-funnel for sugar. The incisions are found to be just of 

 the right shape to make the overlaps in the rolling, and to retain 

 them rolled up with the least tendency to spring back. After 

 some other operations destined to facilitate subsequent parts of its 

 task, the beetle enters the rolled-up part of the leaf and brings 

 it more perfectly together; it again comes out, and, pursuing a 

 different system, holds on with the legs of one side of the body to 

 the roll, and with the other legs drags to it the portion of the leaf 



