and spreads an infinity of nits, which, when hatched, fill the whole part, and produce excessive anguish; and the difficulty of dislodging them becomes very great. They penetrate to the very bones; and, even when the sufferer has got rid of them, the pain will last until the flesh and skin are entirely healed.

The operation of extracting these insects is long and painful. It consists in separating, with the point of a needle, the flesh next to the membrane where the eggs are lodged; which is not easily done without bursting the tunicle. After having separated even the most minute ligaments, the nest is to be extracted. If unfortunately it burst, particular care must be taken to extract every root of it, and especially not to leave behind the principal insect. This would begin to lay its eggs again before the wound could be healed; and, penetrating much further into the flesh, would increase the difficulty of extracting it. During the great heats, extreme care must be taken not to wet the part affected. Without this precaution, experience has proved that the patient is subject to consequences that frequently prove fatal.

"The Chigoe," says Stedman, "is a kind of small sand-flea, common in Surinam, which gets in between the skin and the flesh without its being felt, and generally under the nails of the toes: where, while it feeds, it keeps growing till it becomes of the size of a large pea, causing no further pain than a disagreeable itching. In process of time its operation appears in the form of a small bladder, in which are deposited thousands of eggs or nits, and which, if it breaks, produce so many young Chigoes, that in course of time create running ulcers, which are often of very dangerous consequence to the patient; so much so, indeed, that he knew a soldier, the soles of whose feet were obliged to be cut away before he could recover; and some men have lost their limbs by amputation, nay, even their lives, by having neglected, in time, to root out these abominable vermin. The moment, therefore, that a redness and

itching, more than usual, are perceived, it is time to extract the Chigoe that occasions them. This is done with a sharp-pointed needle, taking care not to occasion unnecessary pain, and to prevent the chigoe, or bladder, from breaking in the wound. Tobacco ashes are put into the orifice, by which, in a little time, the sore is perfectly healed."

OF THE TICKS IN GENERAL.

These troublesome insects live chiefly on other animals: some of them, however, inhabit the water, and others subsist on various vegetable substances. They are to be found every where, and in immense numbers. The larva and chrysalids have each six feet.

Their mouth is not furnished with a proboscis, but the sucker has a two-valved, cylindrical sheath. They have two compressed feelers, as long as the sucker; two eyes, one on each side of the head; and eight legs.

THE CHEESE-MITE*.

To the naked eye, these minute creatures appear little more than moving particles of dust; but on the application of the microscope they are found to be perfect insects, performing all the regular animal functions.

The females, which are easily distinguished from the males, are oviparous. The eggs are so minute, that on a tolerably accurate calculation it appears, that ninety millions of them would not fill the shell of a pigeon's

* DESCRIPTION. The head of the Cheese-mite is small in proportion to the rest of the body. Its legs are furnished at the extremities with little claws, by which it is enabled to lay firm hold of the substances it inhabits. The body is furnished with long hairs, which it has the power of depressing; and by this means it is enabled to creep through crevices that would not otherwise admit its body to pass.

SYNONYMS. Acarus Siro. Linn.-La Mitte ciron. Tigny.

egg. During warm weather they are hatched in about twelve days; but, during winter, the time of hatching is much longer. When the young-ones first come forth they are extremely minute; and before they attain their full size, they cast their skins several times.

Mites are very quick-sighted; and when once they have been touched with a pin, it is easy to perceive a great degree of cunning exerted to avoid a second touch. They are extremely voracious animals, and are often observed even to devour each other; and so very tenacious are they of life, that they have been kept alive many months between two concave glasses, by which they were applied to a microscope. Leeuwenhoek placed a female Mite on the point of a pin for examination: she remained there ten days, and during the time laid two eggs; which, for want of other food, she devoured.

THE DOG-TICK *.

In thickets and heaths these Ticks are sometimes: very abundant. Hence it is that animals which frequent such places, and particularly dogs of the chase, are much exposed to their attacks.

Their abdomen is quite flat and thin when they have been long without nourishment; but, when adhering to the body of an animal, they soon fill themselves with blood, and their size then becomes so much enlarged, that any one unacquainted with their habits and appearance, would scarcely recognise them.

Their motions are extremely slow and heavy, but, in compensation for this apparent defect, they are able to adhere closely and strongly even to the most solid bo

DESCRIPTION. The body, when filled with blood, is nearly globular. The abdomen is livid, with a round, brown spot at the base.

SYNONYMS. Acarus ricinus. Linnæus.-Ixode ricin. Latreille. La Tique. Cuvier.

dies. They are very tenacious of life; and their skin is so hard and tough, that they are not easily susceptible of injury. Long after they are deprived of their head, they give indications of remaining life.

In the destruction of these insects, mercurial preparations have been employed with success.

THE HARVEST-BUG *.

During the months of August and September, the Harvest-bug, in some of the southern counties of England, is a troublesome and disagreeable insect. By means of two claws situated above the upper legs, it adheres so firmly to the skin as not easily to be disengaged. Wherever it fixes it causes a tumour about the size of a pea, or larger, accompanied by a most unpleasant itching.

Harvest-bugs abound upon plants, and are generally caught from walking in gardens, among long grass, or in corn-fields. Mr. White says, they are so numerous on the chalky downs of Hampshire, that the warreners' nets are frequently discoloured, from the immense numbers that get upon them; and that the men are sometimes so bitten by them as to be thrown into fevers.

OF THE SPIDERS IN GENERAL+.
These insects, which are so remarkable, on account

DESCRIPTION. The Harvest-bug is of a somewhat globular shape, and of a bright red colour, with the abdomen bristly behind. It is smaller than the common mite, and is but just perceptible when on the skin. Shaw.

SYNONYMS. Acarus Autumnalis. Autumnal Acarus, or Harvest-bug. Shaw's Nat. Mis.

+ Spiders have short horny jaws, and two incurved, jointed, and sharp feelers. They are destitute of antennæ; and have eight or sometimes only six eyes, and eight legs. Their abdomen is hairy, and furnished with papillæ, from which they spin their webs.

of their industry and manners of life, are generally viewed with an aversion only to be accounted for by the unpleasing impressions that are made upon us in early life. These impressions are, in general, communicated by persons ill qualified to give the mind that direction which is necessary for the purposes of life. Even many naturalists have complained that this aversion has deterred them from observing and accurately examining the habits of these insects; and those who have undertaken to do so, have generally been at much trouble to overcome their antipathy. Roesel accustomed himself to view the insects first at a distance: he then considered their webs; and, at last, he ventured to look at the insects themselves, through a microscope. Göze viewed individual parts of Spiders, till he was able to look, without any sentiment of aversion, at the entire insect. Both these naturalists so far conquered their antipathy, that they could afterwards handle and examine Spiders with perfect indifference.

Spiders prey on other insects, and do not, in all cases, spare even their own species. There is little doubt but their bite is venomous; and it is said that a fly which has once felt it can never be recovered, but soon dies in convulsions. Many of the species have been swallowed, without any subsequent inconvenience.

Some of the Spiders spin webs for the purpose of catching their prey; but others seize it by surprise. They are all able to sustain an abstinence from food for a great length of time; some for even six months, or upwards.

They frequently change their skins. The larva and pupa have each eight legs, and differ in no respect from the perfect insect.

THE HOUSE-SPIDER *.

House-spiders feed principally on flies; and the web

* DESCRIPTION. The abdomen of these insects is nearly