bers in all the seaport towns of this country, and particularly in the metropolis, being conveyed thither in clothes, packages, &c. Hence appears the great necessity of examining carefully every thing brought from such vessels into the houses.

Deal and beech boards should be removed, as should also every thing that is fixed to a bed by means of paste, as these afford them both shelter and food. Oak and mahogany are probably the best kinds of wood to use, as the closeness of their texture allows the animals but an uncomfortable situation.

It is supposed that Bugs do not altogether lie torpid during the winter, but that in the cold weather they require less nutriment; and therefore that they are not tempted to come so often out of their retreats, as they do in the warmer seasons of the year.

THE PARADOXICAL BUG*.

"That singular insect, the Cimex Paradoxus, which (says Dr. Sparrman) I have described, and of which I have given a drawing, in the Swedish Transactions, I discovered at this place, (the Cape of Good Hope,) as at noon-tide I sought for shelter among the branches of a shrub, from the intolerable heat of the sun. Though the air was now extremely still and calm, so as scarcely to have shaken an aspen leaf, yet I thought I saw a little, withered, pale, crumpled leaf, eaten as it were by caterpillars, flitting from the tree. This appeared to me so very extraordinary, that I thought it worth while suddenly to quit my verdant bower, in order to contemplate it; and I could scarcely believe my eyes, when I saw a living insect, in shape and colour resembling the fragment of a withered leaf, with the edges turned up and eaten away, as it were, by caterpillars, and at

*See Plate xix. Fig. 5.

SYNONYMS. Cimex paradoxus. Linn. Gmel.-Acanthia paradoxa. Fabricius.

the same time all over beset with prickles. Nature, by this peculiar form, has certainly extremely well defended, and concealed as it were in a mask, this insect, from birds and its other foes; in all probability with a view to its preservation, and to employ it for some important office in the system of her oeconomy; a system with which we are too little acquainted, in general too little investigate, and, in every part of it, can never sufficiently admire with that respect and adoration, which we owe to the great Author of Nature, and Ruler of the Universe."

OF THE APHIDES, OR PLANT-LICE*.

The minute animals which compose this singular tribe, live entirely on vegetables, and the loftiest tree is as liable to their attacks as the most humble plant. Their numbers are often incalculably great. They prefer the young shoots, on account of their tenderness, and frequently insinuate themselves into the very hearts of the plants, doing irreparable mischief even before they are discovered. But, for the most part, they beset the foliage, and are always found on the underside of the leaf. This they prefer, not only on account of its being the most tender part, but because it affords them protection from the weather, and from various injuries. to which they would otherwise be exposed. Sometimes, though rarely, the root is the object of their choice; and the roots of lettuces have been observed so thickly beset with one of the species, that a whole crop has been rendered sickly and of little value. They are rarely to be found on the bark of trees.

*The beak of the Aphides, the sheath of which is composed of five joints, is inflected. The antennæ are tapering, and longer than the thorax. These insects have either four wings, or are entirely destitute of wings. At the abdomen there are two obtuse erect horns; and the tail is sometimes terminated by a small style.

Some of the species are constantly and unalterably attached to one or more particular kinds of plants; but others feed indiscriminately on most sorts of herbage.

These insects are sometimes winged, and sometimes destitute of wings, without any distinction of sex. In the spring they are viviparous, producing their offspring alive; and in the autumn they are oviparous, depositing their eggs, like most other insects, in places where they remain secured through the winter till the ensuing spring, when they are hatched. The Aphides afford also another surprising deviation from the general laws of nature; one impregnation of the female is sufficient for nine generations.

The larva, chrysalids, and perfect insects, have so little difference in external appearance, that they cannot be distinguished from each other.

THE APHIS OF THE ROSE-TREE*.

Towards the beginning of February, if the weather be sufficiently warm to make the buds of the rose-tree swell and appear green, this species of Aphis will be found on them in considerable abundance. They are produced from small, black, oval eggs, which were deposited in autumn on the last year's shoots. If, after their appearance, the season become cold, almost the whole of them suffer, and the trees, for that year, are in a great measure freed from them.

Those that withstand the severity of the weather, seldom arrive at their full growth before April, when, after twice casting their skins, they begin to breed. It

* DESCRIPTION. This insect, which is well known by the name of Rose Louse, is generally of a green colour, with the tip of the antennæ and horns black. The tail is pointed, and without a style.

SYNONYMS. Aphis Rosa. Linn. Gmel.-Rose Louse, or Rose Aphis.

then appears that they are all females: each of them produces a numerous progeny, and that without any intercourse with a male insect. The young-ones, when they first come from the parent insects, are each enveloped in a thin membrane, that has the appearance of an oval egg. This apparent egg adheres by one extremity to the mother, while the young Aphis proceeding from it, extends the other extremity; by this means gradually drawing the ruptured membrane over the head and body to the hind feet. During the operation, and for some time afterwards, the fore part of the head adheres, by the viscous matter about it, to the tail of the parent. Thus suspended, the young insect soon entirely frees itself from its former envelopement; and, when its limbs become a little strengthened, it is set down on some tender shoot, and there left to provide for itself.

In the spring months there appear but these two generations of the Aphis: the warmth of summer, however, produces no fewer than five. One of these comes forth in May; and the months of June and July supply each two more. The insects of the May breed cast their skins twice, and the others three or four times, according to the warmth of the season. When the heat has been sufficiently great, and the food is in tolerable plenty, the first change has been observed to take place in about ten days after their production.

Early in June, some of the third generation, which were produced about the middle of May, after casting their last covering, discover four erect wings, much longer than their bodies. The formation of the wings seems to depend not on sexual distinction, nor even on the original structure of the insects, so much as on the quantity and quality of the nourishment with which they are supplied. Few of those which live on succulent shoots, have wings, while those of the same generation, on the less tender branches, are most of them winged. Some time before they attain their full growth, it is easy to discern which of them will have

wings, from a remarkable fulness of the breast. When the last covering is rejected, the wings, which before were folded in a very narrow compass, gradually extend, in a most beautiful manner, to their proper size and dimensions. All the subsequent breeds are winged.

In the autumn, the eighth, ninth, and tenth generations are produced; two in August, and the last about the middle of September. The two first resemble the summer breeds, but the third differs very greatly from all the rest. Though all the Aphides which have hitherto appeared, have been females, in this tenth generation several male insects are found. The females have at first the appearance of the summer insects; but in a few days their colour changes from green to yellow, and gradually, before their full growth, to orange. These yellow females are destitute of wings. The males, when they first appear, are of a reddish brown, but afterwards, when they begin to thicken about the breast, they have a dark line along the middle of the back. They attain their full growth in about three weeks, and then, casting their last skin, they appear in every part, except the wings, of a bright yellow colour. They, however, shortly afterwards, become dark brown. The wings become transparent, and at length are in appearance not unlike very fine black gauze. The females soon begin to deposit their eggs, which, if possible, is always done near the buds of the branches, that the future young-ones may be the more easily supplied with nourishment. Some of them continue to lay their eggs until the beginning of November: these eggs are oval, and, when first protruded, are green, but they soon become perfectly black. They adhere to the branches on which they are deposited, by the viscous matter that at first surrounds them. These eggs remain through the winter, till the ensuing spring, before they are hatched.

If the Aphides had not many enemies, their increase in summer would sometimes be destructively great,