hue, but now it is changed into a sordid yellow.* The shining of the rind disappears. Probe it with a pin, the water issues in abundance; cut it with a knife, and the parenchymatous part appears putrefied; scarification to the quick or sound part is the only remedy. If the root and branches be diseased, root it out, change the earth, and replace it by another plant. The Opuntia of Campeachy is particularly subject to this disease. The gum is the third disease to which the Nopals are subject. The part swells through which the gum issues, without the substance or colour of the plant being altered; it forms a fissure an inch or more in size; a liquor oozes from it, and fixes itself in tears like a mealy opaque gum, yellow in the Nopals, and white in those of Castile. These are very subject to this disease. Perhaps the root, which is extremely vigorous, (and being too gluttonous) furnishes more sustenance than what is necessary for the articulations. This sap, accumulating in the uterculi of the plant, produces an effort to discharge itself in an extraordinary way.

It has been remarked, on examining the course of the canal in which it is collected, that the discharge is somewhat white, like milk, and less fluid than the sap, which is generally clear and fluent.

Some of these observations, which I have translated from the French, are worthy of the attention of medical men; and may, with great truth, be applied to the human system.

We are informed that rats and mice are fond of the Nopal, and that many of the beetle tribe riot on its luxuriant juices.

THE COCHINEAL INSECT.

THE ancients supposed that the Cochineal insect was the product of a plant; the word Coccus signifying a red colour, accord

* Is not this like some of the diseases to which the human frame is subject in warm climates?

†Traite de la culture du Nopal, et de l'éducation de la Cochenille dans les Colonies Françaises de l'Amérique, &c. Par M. Thiery de Menonville, Avocat en Parlement, Botaniste, &c. &c.

Au Cap-François, Chez la veuve HERBAULT, Libraire de Monseigneur le general & du Cercle des Philadelphes.

ing to Lampride, Martial, and Pliny the elder. Many passages in the works of the latter, show that this naturalist believed in the common opinion, that the Cochineal was a grain, the production of a tree. The celebrated Linnæus retained the word Coccus to designate a family of insects, under the order Hemiptera, genus 9th, the character of which he gives as follows: "Rostrum pectorale; abdomen postice setosum. Alæ duæ erectæ masculis. Feminæ apteræ.. Antennæ setaceæ.”

Twenty-two species of insects are arranged under this generic definition; in their number, is the Coccus of the Cactus Cochinilifer. The Cochineal has been likewise named, from its resemblance to the Coccinella, an insect of the order Coleoptera. This name is evidently a diminutive of the word Coccus. The Coccus inhabits the Cactus Cochinilifer. The abdomen is flat, the back hemispherical and furrowed by transverse wrinkles, which meet on the belly by a double margin, the superior of which is the least; the skin is of a dark brown. Its mouth is an awl-shaped point, which issues from the middle of the thorax; it has six very short, brown feet, and is without wings. The body of the male is longer than that of the female, of a deep red colour, covered by two wings; it has two antennæ, which are one-third longer than the body; the abdomen is terminated by two bristles or hairs, which diverge like the antennæ; it has likewise six feet, larger than those of the female; its flight is usually confined to a short space; it is called, by the Mexicans, Grana. This name is evidently a continuation of the old error, which assigned it a place among the vegetable productions. Two kinds of Cochineal are collected in Mexico, the Grana Fina and the Silvester or wild species.

THE SILVESTER.

THE Silvester, or wild Cochineal, is sometimes called Grana Silvestra, a name purely Spanish. This name also prevails by custom among the Indians, who believe that it naturally lives on the wild Nopal, and the Tunas of Mexico. The male and female of this insect differ from each other at different periods of

their age. The young Cochineals fix themselves on the articulations of the Nopal, and insert their rostra into the rind. Is the rostrum simply an awl-shaped point? or is it a tubulous body in the form of a trumpet?

Thirty days after the male insect is brought forth, it appears under the form of a handsome fly; its colour is of a deep red, bordering on purple, equally elegant in form, as he is brilliant in attire. He flies a short distance in quest of a female; he is not much embarrassed in making a choice; he turns around a female, accosts her, and pursues the impulse of nature. After the consummation of the union, he dies the same day, often the same hour. Eight days after the Cochineal has inserted its rostrum and fixed itself on a plant, the hairs on the margin of its back increase in size and frequently in number. The white down, with which the female insect is covered, increases with her age, and adheres firmly to the plant, which sometimes renders it difficult to remove her; a part of the downy substance will remain on the plant. The female is in a proper state for fecundation thirty days after her birth. The term of gestation is also thirty days; during the first ten days, she increases rapidly, and attains to half the size of a garden pea. The day of her accouchement, she pays the same debt of nature as the male. The insects should be placed on the plants of the Nopalry, as soon as they begin to leave their mothers, as it is impossible to transfer them from one plant to another, after they have once inserted their rostra ; on which account, if the Nopal dies, the insects also die. The Silvester being placed on the Nopal, propagates without much care. They may be collected every two months, care being taken to leave a few on each plant to keep up the stock. The downy substance, which remains on the articulations of the Nopal, after the insects are collected, should be rubbed off with a moist cloth. By this means, the eggs and chrysalides of insects that have perished, may also be removed. It appears impossible to collect the Cochineal Silvester to advantage from the Opuntia with thorns; the most expert labourer, it is said, would not be able to collect two ounces per day, in consequence of the difficulty which the thorns present; but the same labourer would be able. to collect, from the garden Opuntia, several pounds.

The sowing of Cochineal, a term used in many French and Spanish writers, is certainly an erroneous expression, which arose from the belief that the Cochineal was a vegetable grain. Eighteen months after a Nopalry has been planted, it is in a state for the reception and nourishment of the insects. The most settled spring month, I conceive, would be the most proper in which to commence the treatment of the Cochineal insect, in our climate. The Nopalry should therefore be planted at a period, when the plants will arrive to a proper age or time of commencing the treatment of the insect; say April, for example. If a Nopalry were planted in September or October, 1810, it would be in a proper state to receive insects in April, 1812, if no accidents should befall the plants. This is necessary, provided a large crop of insects is expected; but small plants will be sufficient to nourish a few. The female insects should be put into nests, as I have already mentioned in a former part of this essay. It is recommended to place the young insects on the plant early in the morning. Not more than two or four mothers should be placed on a Nopal of two articulations. On a Nopal composed of a hundred, two, three or four hundred may be distributed by fours in á hundred nests, or eight to fifty. Particular directions are given on this head; but it appears necessary to put as many only on each articulation as the plant can nourish. We are advised to make choice of the largest females for the nests. The nests should be suspended on the plants and exposed to the sun, that a moderate degree of heat may induce the young insects to quit them; care being also taken to consult their ease in making their escape. The first nest may be placed about a foot, or a foot and a half, from the earth.

Two months after the Cochineals have been placed on the plant, or one month after their connexion with the male, the young begin to present themselves. This is the moment when a general collection should be made, preserving a few breeders; no time is to be lost. At this period, friends, neighbours, whole families, young and old, unite to make the collection as speedily as possible; it is a day of festivity in Mexico. Each person is armed with a blunt knife, in his right hand, like that of a dressing case,

by which the insects are raised from the plant, without doing injury to either. They are caught in the left hand, and put on a plate or into a napkin, attached to the body by its four corners. A child of ten years of age can collect ten pounds per day, which, when killed and dried, shrink to three pounds and a half.

When they are taken out

The insects are killed by putting them into baskets, of a convenient size, say two feet in diameter and one in depth, for ten pounds. Being covered with a coarse cloth, they are to be immersed in boiling water; and must be entirely covered. In this they may remain one, two, or three minutes; it is said that there is no danger of dissolving the insects by this method. The operator should be careful not to wound them, as those that are bruised are very difficult to dry. The water is always more or less coloured, but the loss is trifling. of the water, they should be spread with care on a table, or plates of brass or tin, and exposed to the heat of the sun. They will generally dry in the course of the day, provided care be taken to turn them occasionally with the hand about mid-day. Should they be not perfectly dry on the first day, they must be again exposed, until all moisture be dissipated, otherwise there will be danger of their spoiling by corruption. Ten persons may prepare two hundred pounds of Cochineal Silvester in one day, without fatigue. This method of killing and drying the Silvester, we are informed, is far preferable to heated plates or ovens, by which the grains are frequently burnt.

GRANA FINA, OR THE TRUE COCHINEAL.

THE difference of price between the fine Cochineal and the Silvester, indicates the superiority of the one over the other, and invites the cultivator of the Nopal to prefer it. Two Nopals of the same size, being charged with the same species, produce different quantities of Cochineal. That with the fine, always affords one-third more, in weight, than the other, charged with the Silvester. The female Cochineals bring forth young in the same manner as the Silvester, two months after their birth, thirty days after their union with the male. They appear then about