FIG. 63.

h.

horns on the upper side of the extremity of the body, the under side being furnished with a fleshy retractile tubercle, which the insect uses as a seventh foot. When full grown it descends to the earth, where it buries itself to a considerable depth, forming for itself a small oval cocoon of earth, with the inner surface quite smooth. Here it assumes the ordinary pupa state to which all coleopterous insects are subject." The perfect insect is a small, buff or slaty-brown, oval beetle, about one-sixth of an inch long, with knobbed antennæ (e), which is seen flying about the raspberry plants in summer, and is sometimes also found on the hawthorn and blackberry. In fig. 63, f is the larva magnified, and g the cocoon of earth, open at one end: h is the pupa seen on the under side, and i the perfect insect, both magnified; the lines showing the natural length of each.

i

The Raspberry Beetle in its various

states.

In this month the leaves of cherry, pear, quince, and plum trees are often infested with a very singular kind of insect, which resembles a small black slug, and which is covered with a slimy secretion, which has a most disagreeable and sickening appearance. These insects feed only on the upper surface of the leaves, as shown at a in fig. 64, which they entirely destroy, leaving the under part untouched, so that the leaf is left entire, though it appears as blighted and shrivelled as if it had been scorched by lightning; and in the course of a few weeks the leaves drop off, as though winter had come upon them prematurely. When feeding, the front of the body of this grub is inflated (as shown at b), and the hinder segments narrowed, so that the insect somewhat resembles a minute tadpole, or rather the excrement of a sparrow or a swallow, or a drop of black paint, which appears to have accidentally fallen upon the leaf; but on taking off its slimy covering a fleshy caterpillar will be discovered, as shown, greatly magnified, at c in fig. 64. The head of the larva, seen in front, is shown at d, and e is one of the mandibles: one of the lower jaws is shown at f, and the lower lip at g. The insect remains during

the day perfectly quiet, with its head drawn inwards, so as to be completely hidden, but at night it crawls slowly about from branch to branch. It changes its skin two or three times, leaving its former covering (0) attached to the leaves, on which it appears

like a short piece of black thread, with a knot at one end, the knot being generally shining. These exuviæ may often be seen on the leaves of various fruit trees, and on those of the hawthorn, in the month of July, at the latter end of which month, or the

FIG. 65.

The perfect Insect and Cocoon of the Slimy Grub of the Pear Tree.

beginning of August, the insects enclose themselves in cocoons, like that shown at h in fig. 65. When they first change their skin, they are of a clayey colour, and destitute of slime, and at this time they will occasionally bend their bodies so as to make the

head and tail meet.

In a few days, however, the slime appears, and the insect resumes its previous habits. When about to enter into the cocoon state, the movements of the animal become extremely sluggish, and it crawls to the under side of the leaf; the cocoon is brown, and covered externally with small particles of earth, which are fastened together with silken threads. The insect was described by Linnæus as the Saw-fly of the Cherry, and he called it Tenthredo cerasi, as he conceived that its ravages were confined to the cherry. Modern entomologists, however, finding that it attacks several plants, and that it differs from the common Saw-flies, have changed its name to Selandria æthiops. In fig. 65, i represents the perfect insect of its natural size, and k shows it greatly magnified. It is extremely difficult to destroy these insects. Mr. Major recommends dusting the trees, when dry, with quicklime; but Mr. Fox of Little Dalby Hall, Leicestershire, who sent some leaves of a peartree covered with the larvæ of these insects to the Gardener's Magazine, mentions that dusting the insects with quicklime had no other effect upon them than to make them cast off their outer skin, and assume the yellow clay-like appearance above mentioned. "In four hours after the operation," he continues, "they had fixed themselves to another part of the leaves as firmly as if nothing had been done to them." Mr. Westwood, however, thinks that this result was only owing to the insect being then just about to change its skin, and that the effect of the lime would have been quite different at any other period.

Another mode of destroying this insect is as follows:-" To thirty gallons of water, add a peck of quicklime, and after standing a few hours pour it gently off to prevent any of the sediment mixing with the liquid, and add two pounds of soft soap, with which one pound of sulphur has been well mixed previously to putting it in the water; then add two gallons of a decoction of artichoke leaves, and one gallon of tobacco liquor. The ingredients should be well mixed together, and then kept for use. When the mixture is to be used, it should be in the proportion of one-third to two-thirds of pure water, and it should be applied with a garden engine, from three to seven o'clock in the evening, after a fine dry day, or between five and eight in the morning, if no dew has fallen the previous evening. From two to six washings will be found sufficient to clean the trees; and if the mixture be used on those trees that are not infested, it will be found a great means of preventing them

from becoming so. To make the decoction of artichoke leaves, take twenty-eight pounds of leaves, and boil them in twelve gallons of water for half an hour. Then strain off the liquid, and, letting it stand till cold, barrel it, to be used as wanted. This decoction of artichoke leaves will be found very useful to wash infested trees with, as in many cases it will destroy the insects alone. An infusion of elder leaves, formed by pouring boiling water upon them, is also a very useful thing to wash trees with, as it will destroy many insects, particularly when they are first hatched."

A branch attacked by the Larva and Pupa of the Small Ermine Moth. Another very destructive insect which attacks the leaves of fruit and other trees about this season is the caterpillar of the small ermine moth (Yponomeuta padella). The apple, the hawthorn, and the bird-cherry are particularly subject to the attacks of this insect, and in the month of July they may be seen completely covered with webs, which hang suspended from their branches in festoons, sometimes reaching the ground, and even spreading over the earth be

66

neath the tree. It is peculiar in this insect that it is found in numbers together, not only in its caterpillar but in its pupa state, the caterpillars feeding together under the shelter of a web, as shown at a in fig. 66, and the cocoons being formed under the shelter of a similar web, as shown at b. The webs under which the caterpillars feed, Mr. Westwood informs us, are quitted from time to time, and new encampments established at short distances from each other: hence each brood constructs several webs in the course of its caterpillar state; the reason of which is, that the caterpillars do not quit their webs to feed, but only eat such leaves as are enclosed in each web. The number of inhabitants in a colony varies from one hundred to two hundred; and hence the more numerous the colony the more frequently is a change of residence required. These webs consist of a great number of threads, not unlike spiders' webs, arranged somewhat irregularly, but sufficiently loose to enable the inhabitants to be seen through the covering. The caterpillars eat only the parenchyma of the upper side of the leaf; they also arrange their threads longitudinally, each apparently having a thread of its own, along which it moves, either backwards or forwards, without disturbing its neighbours, which when in repose are arranged side by side. The larger-sized nets include several of the smaller branches or twigs, with their leaves; and some parts are of a firmer texture than the rest, apparently for resisting the wet. When the parenchyma of the upper sides of the leaves enclosed in the web has been consumed, the nest is abandoned and a new one made, enclosing a fresh bunch of twigs, each of the caterpillars spinning a considerable number of threads; and thus each colony constructs as many as six or eight distinct webs, disfiguring the tree, especially when, as is often the case, there are many societies established upon it. The leaves thus half consumed wither up, as well as the young branches, for want of support, and the tree assumes the appearance of having been entirely scorched up with fire. The caterpillars rarely quit their nests; but when alarmed or disturbed, they endeavour to make their escape by spinning a long thread, and dropping to the ground. When touched also they writhe about with great activity, and will run backwards nearly as fast as forwards. When full-grown, as shown at g in fig. 67, about the beginning of July, each caterpillar encloses itself in a long and nearly cylindrical cocoon of white silk (d), of a leathery consistence; and these cocoons are arranged side by side at one end of the nest, form