318 PYRUS MALUS. 
tioned in several important particulars. It is one of the kind in which the body 
of the female is not large enough to cover her eggs, for the protection whereof, 
provision is made, consisting, in this species, of a kind of membraneous shell, of 
the colour and consistence almost of paper. In autumn, and during winter, these 
insects are seen in a torpid state, and of two different forms and sizes, on the bark 
of the trees. The larger ones measure less than a tenth of an inch in length, and 
are in the shape of a common oyster-shell, being broad at the hinder extremity, 
but tapering towards the other, which is surmounted by a little oval, brownish 
scale. The small ones, which are not much more than half the length of the 
others, are of an oblong-oval shape, or almost four-sided, with the ends rounded, 
and one extremity is covered by a dark-coloured, minute, oval scale. For a 
description of the general habits of this family of insects, the reader is referred to 
our article on the orange-tree, under the head of " Insects."* 
The tender buds and young leaves of the apple-tree are sometimes attacked, in 
May and June, by multitudes of small caterpillars, described by Dr. Harris, 
under the name of the eye-spotted penthina {Penthina ocula?ia.) They are of 
a pale and dull-brown colour, warty and slightly downy, with the head and the 
top of the first ring of a dark shining brown. They usually acquire their growth 
by the middle of June, at which time they transform, and come out in the winged 
state early in July. These caterpillars live singly in the buds or opening foli- 
age, which they fasten together and devour. The only sure mode recommended 
to destroy them is, to crush the withered clusters of leaves containing them or 
their chrysalides, and thus " nip them in the bud." But one of the greatest 
pests to the American orchards, as well as to the foliage of the elm, and some- 
times of the cherry, plum, linden, and other trees, is the canker-worm, first 
described by Professor Peck under the name of Phalcena vemata. According to 
Dr. Harris, the canker-worm moths begin to make their appearance after the 
first hard frost in the autumn, usually towards the end of October, and they con- 
tinue to come forth, in greater or smaller numbers, according to the mildness or 
severity of the weather after the frosts have begun. Their general time of rising, 
however, is in the spring, beginning about the middle of March, but sometimes 
before, and at others, after this time ; and they continue to come forth for the 
space of about three weeks. It has been observed that there are more females 
than males among those that appear in the autumn and winter, and that the 
males are the most abundant in the spring. The sluggish and wingless females 
instinctively make their way towards the nearest trees, and creep slowly up their 
trunks. In a few days afterwards they are followed by the winged and active 
males, which flutter about and accompany them in their ascent, during which, 
the two sexes pair. Soon after this, the females lay their eggs upon the branches 
of the trees, placing them on their ends, close together in rows, forming clusters 
of sixty to one hundred eggs or more, which is the number usually laid by each. 
The eggs are glued to each other, and to the bark, by a grayish varnish, which 
is impervious to water; and the clusters are thus securely fastened in the forks 
of the small branches, or close to the young twigs and buds. The eggs are usu- 
ally hatched between the first and the middle of May, or about the time that the 
red currant is in blossom, and the young leaves of the apple-tree begin to expand. 
The little canker-worms, upon making their escape from the eggs, gather upon 
the tender leaves, and, on the occurrence of cold and wet weather, seek shelter 
in the bosom of a bud, or into the flowers, when the latter appear. The leaves, 
when first attacked, will be found pierced with small holes, which become larger 
and more irregular as the worms increase in size, until nearly all the pulpy parts 
are consumed. A very great difference of colour is observable among these 
* See also Harris' Report, pp. 201 et 203. 
