PREVENTING THE ATTACK OF INSECTS, MILDEW, &c. 171 
I 
affect both; and both require defences against attack, or the applica¬ 
tion of some remedy after the attack. 
Plants are preyed on by insects and by parasites of their own kind; 
both disfigure and destroy the organisation. Whatever the disease or 
enemy be, it is much more injurious in the early stages of the annual 
growth of trees than after the foliage and wood have gained a firmer 
consistence ; and therefore the earlier a preventive or remedy is applied, 
the more effectual it is likely to prove. 
It is perfectly well known that the eggs of the insects which are 
such an annoyance in gardens during the spring and summer, are laid 
on, or very near the plants which yield their progeny food. These 
eggs are deposited in regular or irregular clusters on the bark, and 
particularly round the bases of the buds. When examined in this 
state the eggs appear to be glued together and covered by some exuda¬ 
tion from the parent, which at once conceals, secures, and preserves 
the little embryos till the warmth of the spring brings forth the tender 
leaves or flowers and the puny larvae together. At first the larvae of 
moths are very minute caterpillars, and soon as they have burst their 
investments instinctively crawl to the bursting bud, where they rest and 
feed. The little grey moth ( Yponomenta paclella) is one of the smallest 
but most numerous of its tribe. We have often had to regret the 
extensive damage committed by this tiny caterpillar, particularly oil 
the foliage of nonpareil apple-trees in a sheltered orchard ; not a leaf 
escaped, and though the fruit were not preyed on, they were useless, 
having neither juice nor flavour. The economy of this insect has never 
been more minutely studied and described than by Mr. R. H. Lewis, 
in a late number of the Transactions of the Entomological Society 
. of London. Mr. Lewis states that “The mother moth deposits her 
eggs generally on small twigs, and chiefly on their under surface, in 
a circular patch about a line and a half in diameter, which she covers 
with a strong gluten, at first of a pale yellow, but which is afterwards, 
by the action of the atmosphere and rain, changed to a dark brown, 
very closely resembling the bark of the tree, and is then very difficult 
to be distinguished from it. The eggs hatch early in autumn, and the 
larvae remain in confinement during the whole winter, under the cover¬ 
ing which is formed by the gluten and egg-shells. If one of these 
nests be opened it will be found hollow, and containing from twenty 
to thirty pale-coloured larvae, with head and a spot on the shoulder 
black. In these receptacles they increase somewhat in size : the bark 
of the tree beneath is moist and green, but whether they derive any 
nourishment from it the writer cannot tell. About the time the trees 
are coming into leaf they make their escape, but they do not now com- 
