CHAP. XLII. ROSACEX. PY RUS. 907 
explains the reason of their sudden appearance: it shows how one day not a 
single caterpillar may be visible on the trees, and the next they may be 
swarming with larve of so large a size as to rebut the idea of their having 
been recently hatched. Besides, their latter habit of feeding on the leaves 
externally is so little like their former one of feeding on them internally, that 
any one who had not satisfied himself, by examination, that both habits are 
proper to the same caterpillars, would scarcely suppose this to be the case. 
While the caterpillars are within the leaves, they are of a yellowish colour, 
though they become darker at each change of skin. It is in this state that I 
would recommend their destruction, by gathering and burning every leaf 
which by its outward appearance betrays the internal ravages. Their nests 
are so difficult to discover, that searching for them seems entirely out of the 
question ; and Iam much afraid that, could any wash be conveniently ap- 
plied to the small twigs, whatever might be sufficiently powerful to penetrate 
the glutinous covering would at the same time injure the tree. 
“*< Having satiated themselves with the growing hopes of the gardener, who 
endeavours, but in vain, to stop their destructive career, they prepare for the 
pupa state by spinning white cocoons of an ellipsoidal form. In a short 
time they emerge from their pupz, and may be seen in the evening, but more 
particularly in the early morning, flying by hundreds round those devoted 
trees which are, in the following year, to be the scene of similar ravages, 
unless circumstances for which we cannot account should prevent their mul- 
tiplication.” 
The Larve of various Moths feed on the leaves, and some even penetrate 
into the young shoots, of apple trees. One caterpillar, often found rolled up 
in an apple tree leaf, is of a chestnut-brown colour, with a black head; and 
another is green, with a few black hairs scattered over its body. The eggs of 
some of these moths are deposited in the preceding autumn, upon the 
branches, where they are fixed so firmly and are so little susceptible of injury 
from variation in temperature, that it is difficult to prescribe any application 
that would prevent caterpillars being hatched from them in the following 
spring. 
There is also a moth which lays its eggs in the buds, the caterpillar of which 
eats its way through the bud into the soft wood, in the case of flower buds ; 
and into the herbaceous shoot of the current year, in the case of leaf buds; 
occasioning the shoots and spurs soon afterwards to die. We are not aware 
thatthe economy of this insect has been studied and recorded, though it 
appears to belong to the family of Algérie, These, according to Newman, 
“are produced from almost colourless maggots, which have the penultimate 
segment diminished, and without any horn; which have six corneous and 
pointed, and ten wart-like, and almost useless, feet ; which feed in the interior 
of the trunks of trees, throughout the winter and spring ; and then, spinning 
a cocoon among their food, change into remarkably rough and vivacious 
pup, which in ten or twelve days produce perfect insects.” (Zntom. Mag., 
vol.i. p.71.) See Encyc. of Gard., edit. 1835. art, Apple. 
The common Cockchafer (Meloléntha vuigiris Fab.), in its perfect state, 
attacks the leaves of all trees; and, though it has been found chiefly devour- 
ing those of the oak, (in treating of which tree the insect will be figured and 
described), yet it is also very injurious to those of the apple. Smoking them 
off, or shaking the branches of the tree till they drop to the ground, and then 
picking them up and destroying them, are the only means of alleviating the 
injuries done by insects already in their winged state; and they have the 
further advantage, with reference to the future, that they prevent the insects 
from laying their eggs. (See the article Quércus.) 
Anémala (Scarabe‘us) horticola, a beetle called, in Norfolk, the chovy, is 
there deemed very injurious to apple trees, and to other trees and plants, as 
it feeds both on the leaves and flowers. 
The Aicidium cancellatum (the fungus mentioned as growing on the leaves 
5 . . 
of the pear tree, and producing what is called mildew) is also not unfrequent 
