OF THE LOUSE TRIBE.

Lice live on animal juices, which they extract from living bodies by means of their sucker. The larva and pupa resemble the perfect insect.

The mouth in these animals is formed by a retractile recurved sucker, without a proboscis. There are no feelers, and the antennæ are about the length of the thorax. The abdomen is somewhat flattened; and the legs, which are six in number, are formed not for leaping, but for running and climbing.

THE COMMON LOUSE*.

When we examine the human Louse with the microscope, its external deformity excites disgust. The fore part of its head is somewhat oblong, while the hind part is rounded. The skin is hard and transparent, with here and there a few bristly hairs. On each side of its head are two antennæ or horns, jointed, and covered with bristly hair; and behind these are the eyes, which are large and black. The neck is short, and the breast divided into three parts; on each side of which are three legs, armed at the end with small claws, by which the animal is enabled to lay hold of different objects. The trunk, or proboscis, is generally concealed in its tube: this is very sharp, and furnished, towards its upper part, with a few reversed prickles. By means of this the Louse feeds; and, when it is engaged in sucking any animal, the blood may be seen, through the transparency of its external covering, to rush like a torrent into the stomach. Through the skin its stomach and intestines are visible, as well as the ramifications of the tracheæ or respiratory tubes,

* SYNONYMS. main, in France.

Pediculus humanus. Linn.-Le Pou hu

which appear dispersed, in a beautiful manner, throughout various parts of the animal.

Scarcely any creature multiplies so quickly as this unwelcome intruder. It has been asserted that a Louse becomes a grandfather in the space of twenty-four hours. This fact cannot be ascertained; but nothing is more true than that the moment the nit, which is no other than the egg of the Louse, gets rid of its superfluous moisture, and throws off its shell, it begins in its turn to breed. Nothing so much prevents the increase of this nauseous animal, as cold, and want of humidity. The nits, unless they be laid in a place that is warm, do not produce any thing; and from this it is that many of the nits laid on the hairs in the night-time, are destroyed by the cold of the succeeding day.

In Mexico these animals were so numerous, that the ancient kings found no other means of ridding their subjects of them, than by the imposition of an annual tribute of a certain quantity. Ferdinand Cortes found bags full of lice in the palace of Montezuma.

"This is a creature (says Albin) so officious, that, at one time or other, it will be known to every person; so busy, and so impudent, that it will be intruding itself into every one's company; and withal, so proud and aspiring, that it fears not to trample on the best, and affects nothing so much as a crown. It feeds and lives very high; and that makes it so saucy as to pull any one by the ears that comes in its way; and it will never be quiet till it has drawn blood. It is troubled at nothing so much as that a man scratches his head, as knowing that he is plotting and contriving some mischief against it: this makes it often skulk into some meaner and lower place, and run behind a man's back; hence it is better known than trusted."

OF THE FLEAS IN GENERAL.

The mouth of these insects is without either jaws or feelers it has only a long, inflected proboscis, which

conceals a single bristle. The antennæ are beaded; the abdomen is compressed sideways; and the legs are six in number, and formed for leaping.

The larva are white, cylindrical, and without feet, but are very active little creatures. Under the tail

there are two small spines. The chrysalis is motionless, but in appearance is not unlike the perfect insect. The two following species are all that have been yet discovered.

THE COMMON FLEA*.

Notwithstanding the general disapprobation of this insect, it has certainly something pleasing in its appearance. When examined with a microscope, it will be seen to have a small head, large eyes, and two short, fourjointed antennæ, between which is situated the trunk, or proboscis. The body appears enveloped in a shelly armour, which is always clean and bright: this is beset at the segments with many sharp bristles. All the motions of this insect indicate agility and elegance; and its muscular power is so extraordinary as justly to excite our wonder. We know no animal whose muscular strength can be put in competition with that of a Flea; for, on a moderate computation, it is known to leap to a distance of at least two hundred times its own length.

There is no proportion between the power and the size of the insect tribes. Had man an equal degree of strength, bulk for bulk, with a louse or a flea, the history of Samson would no longer be miraculous. A Flea will drag after it a chain a hundred times heavier than itself; and, to compensate for this power, will eat ten times its own weight of provisions in a day. Mr. Boverich, an ingenious watchmaker, who some years

* SYNONYMS. Pulex irritans. Linn.-La Puce irritante, in France.

ago lived in London, exhibited to the public a little ivory chaise, with four wheels, and all its proper apparatus, and a man sitting on the box, all of which were drawn by a single Flea. He made a small landau, which opened and shut by springs, with six horses harnessed to it, a coachman sitting on the box, and a dog between his legs: four persons in the carriage, two footmen behind it, and a postillion riding on one of the fore-horses, which was also easily drawn by a Flea. He likewise had a chain of brass, about two inches long, containing two hundred links, with a hook at one end, and a padlock and key at the other, which the Flea drew very nimbly along.

This little animal is produced from eggs which the females stick fast, by a kind of glutinous matter, to the roots of the hairs of cats, dogs, and other animals; or to the wool in blankets, rugs, or other similar furniture. Of these eggs the females lay ten or twelve a day, for several days successively; and they are hatched in the same order, five or six days after being laid.

From the eggs come forth, not perfect Fleas, but little whitish worms, or maggots, whose bodies have annular divisions, and are thinly covered with long hairs. They adhere closely to the body of the animal, or substance, on which they were produced; and feed on the scurfy excretion of the skin, the downy parts of linen, &c. They are very small, but lively and active. When alarmed they suddenly roll themselves into the shape of a little ball. They may be kept in a little box, and fed with dead flies, which they eat with great voracity.

In eleven days from their being hatched, they cease to eat, and lie as though they were dying; but, if viewed in this state with a microscope, they will be found weaving a silken covering around them, in which they are to change into a chrysalid form. They continuet nine days in this shape, at first white, and afterwards by degrees darkening their colour as they acquire firmness and strength. As soon as they issue from their

bag, they become perfect Fleas, and are able to leap away.

THE PENETRATING FLEA, OR CHIGOE*.

This is a troublesome insect, too well known in many parts of America. It is so small as to be almost imperceptible. Its legs have not the elasticity of those of fleas; for, if the Chigoes had as great powers of leaping as fleas, few creatures could escape their attack. They are always found among dust, and particularly in filthy places; they fix themselves on the legs, to the soles of the feet, and even to the fingers.

This creature pierces the skin so subtilely that the person is not sensible of the attack; nor is this to be perceived till the insect begins to extend itself. At first, it is not difficult to extract it; but, although it may only have introduced its head, it makes so firm a lodgment that a part of the skin must be sacrificed before it will quit its hold.

If it be not soon perceived, the insect completes its lodgment, sucks the blood, and forms its nest of a white, thin tunicle, in the shape of a flat pearl. It extends itself in this space in such a manner that its head and feet are toward the exterior side, for the convenience of nourishment; and the other part of the body is toward the inner side of the tunicle, in order to lay its eggs there. In proportion as these are laid, the little pearl is enlarged; and in four or five days it is at least two lines in diameter. It is then of the utmost importance to have it extracted; for if this be neglected it bursts,

DESCRIPTION. This insect is chiefly distinguished by the length of its proboscis, which is as long as the body. Its colour is reddish-brown. The abdomen of the female, when with egg, increases to nearly a hundred times the usual size.

SYNONYMS. Pulex penetrans. Linn.-Jigger, Nigua, and Pique, in various parts of America. La Puce penetrante.

Cuvier.