THE OAK MOTH. 295 



leaves, rendering them both stiff and innutritious. The lilacs in 

 my ganien, which are usually covered with these cylindrical 

 Hests of Leaf-roller caterpillars, are comparatively free from 

 them, and the few which exist are very poor specimens, several 

 having been abandoned in a half-made state. In the lilacs of 

 a friend, however, where the soil is about one hundred and 

 twenty feet lower than my own garden, there are plenty of Leaf- 

 roller nests, the ground being much moister than in more elevated 

 situations, and being, moi'eover, on a different soil. 



The mechanics of the Leaf-roller neat are veiy curious, and 

 will be presently mentioned 



One of the most common among the Leaf-rollers is the pretty 

 Oak Moth {Tortrix viridana), which must not be confounded 

 with the oak egger moth already mentioned. It is a little 

 creature with four rather wide delicate wings, the upper pair 

 of a soft leaf green, and the under pair of a greyish hue. In 

 some seasons, the moths, or rather their larvae, are so plentiful 

 that great damage is done to the oak forests, tree after tree being 

 so covered with them that scarcely a leaf escapes destruction, 

 and the growth of the tree is consequently checked. 



Like all Leaf-rollera, they feed on the green substance, or 

 parenchyma of the leaf, and being ensconced within their tubular 

 home can eat without fear of molestation. They are not very 

 much afraid even of the small birds, for as soon as a bill is pushed 

 into one end of the leafy cylinder, the caterpillar hastily "bundles" 

 out of the other — there is no other word which so fully expresses 

 the peculiar action of the larva — and lowers itself towards the 

 ground by a silken thread which proceeds from its moath. In 

 fact, it acts Uke a spider in similar circumstaiices. 



Where these insects are |dentiful, an absurd effect can be 

 produced by tapping the branches of oak trees with a stick. As 

 the stroke reverberates through the branch, the leaves, which 

 appear to the casual passenger to be in their ordinary condition, 

 give forth their inhabitants, and hundreds of tiny caterpillars 

 descend in hot haste, each lowering itself by a thread and drop- 

 ping in little jerks of an inch or two each. Some of them are 

 more timid than the others, and descend nearly to the ground, 

 but the general mass of them remains at about the same height. 

 Another tap will cause them all to drop a foot or two lower, the 



