8s8 



THE NATURE BOOK 



accomplishment. Should the insect fail 

 to project accurately these curves, she 

 will fail also in her attempts to roll up the 

 leaf. Indeed, I think that the Weevil's 

 instinct is by no means infallible in this 

 matter, and that faulty curves account for 

 the many half-rolled and deserted leaves 

 which one may find upon the birch twigs 

 where the insects are at work. 



But in the particular case which, in 

 imagination, we have under observation, 

 we will suppose that our Weevil's curves 

 have been accurately projected. When 

 she has finished the cuts, she takes a long 

 rest — not, I believe, because she is 

 fatigued, but in order that the pendent 

 portion of the leaf may become more 

 flexible. The uncut leaf is stiff with the 

 pressure of the sap. But as soon as the 

 cuts are made the vegetable tissue begins 

 to wither, and becomes gradually quite 

 flabb}^ We see, therefore, that the in- 

 sect's long pause at this juncture is all to 

 her advantage — may, indeed, be regarded 



THE ROLLING HALF DONE. 



as part of her scheme. W^ien, however^ 

 the leaf has become sufficiently pliable, 

 the Weevil goes to its under surface, and 

 standing close to the edge where her 

 original cut begins, commences to roll one 

 side of the leaf round an ideal axis by 

 means of her legs. When watching her I 

 have been irresistibly reminded of a man 

 " on all fours " rolling up an immense 

 sheet of linoleum. 



As one observes the progress of the work, 

 one realises how greatly the Weevil is 

 helped by the curved incisions which she 

 first made. These prove to be exactly 

 what is needed to counteract any ten- 

 dency to spring back on the part of the 

 rolled-up leaf. 



\\lien the Wee\'il has rolled one side 

 of the leaf to the midrib, she alters her 

 tactics somewhat. Holding by the legs 

 on one side of her body to the rolled-up 

 part of the leaf, she drags at the un- 

 rolled portion beyond the midrib with 

 her other legs. In this way she slowly 

 draws the second part of the leaf round 

 the part which she has already rolled, 

 incitlentally wrapping herself within the 

 folds. \Mien the stage shown in the 

 photograph on page 859 is reached, she 

 makes several incisions in the leaf-tissue 

 and lays an egg in each. Thereafter she 

 comes forth, tightens the roll, and fastens 

 down the overlap by means of her jaws. 

 The tip of the leaf now claims her atten- 

 tion. Of it she makes a second and smaller 

 funnel, and bends this inwards so as to 

 close the end of the first funnel. 



Finally, the Weevil ascends the rolled 

 leaf, and partly cuts through the midrib 

 at the point where her first curved cut 

 meets it. She appears to do this with a 

 \iew to promoting that particular state of 

 decay in the leaf which will render it fit 

 food for the grul)S. 



If we trace the life cycle of Wiynchites 

 hetiihe we shall only find additional cause 

 to wonder at the behaviour of the adult 

 insect. The eggs, which hatch in the 

 rolk'tl-up leaf, produce blind and legless 

 maggots. These feed upon the leaf-tissue 

 around them, and wln'n full grown make 

 their way out of the roll and droj) to the 

 ground, wliere, beneath the soil, they 

 ( hange to pu})ce. In this state they pass 

 through the winter, and in the early 

 summer the adult beetle comes forth and 



