Larvae and their Work 



The living leaf is too strong and lengthy to deal with ; 

 a dead leaf would be equally useless to the beetle, for it 

 would be wiry yet brittle. The object of the beetle, 

 therefore, is to obtain a wilted leaf, for in that condition 

 it may be rolled far more easily. The insect, therefore, 

 makes a minute puncture in the leaf stalk, not through the 

 skin alone, but into the parts of the leaf which are bringing 

 nourishment thereto from the stem. This operation 

 causes the leaf to become soft without killing it : brings 

 it, in fact, to the very condition desired by the beetle. 

 Next the industrious little creature, beginning at one 

 edge, rolls the leaf lengthways. Using her feet for the 

 purpose, she holds on to the leaf blade firmly with those 

 on one side and rolls the leaf neatly with those on the 

 other. The task is a laborious one ; her hold on the leaf 

 must never be relaxed or it would fly back like a watch- 

 spring. Methodically she works. As she rolls the leaf she 

 travels from one end to the other ; then, without turning 

 round, she moves backwards, continuing her rolling all the 

 time, a little living shuttle. When the leaf blade is rolled 

 to the midrib, the beetle rolls the other half of the leaf 

 round the portion already rolled, and eventually her 

 labours are at an end, or nearly so. 



When a neat cylinder has been rolled, the structure of 

 the leaf comes to the insect's aid. On its margin there 

 are a number of minute glands which give off a sticky sub- 

 stance. These marginal glands are firmly pressed into 

 contact with the body of the leaf by the beetle, who uses 

 her snout for the purpose. The sticky secretion forms an 

 excellent glue, and the leaf edge remains in position. In 

 the cylinder, the beetle deposits one or more eggs, secure 

 in the knowledge that its larvae will be able to feed with- 

 out fear of molestation. 



The caterpillars of the oak tortrix moth are leaf-rollers 

 which go about their business in quite a different manner 

 from the insects we have just mentioned. They are par- 

 tial to oak leaves. Though they build some remarkably 



86 



