Cochineal (coccus cacti; Span, cochinilla), an insect used as a dye. Other species of the same genus of hemipterous insects, of the bark-louse family, have been used from the remotest periods to afford the material of the brilliant scarlet and crimson dyes of the ancient Hebrews, Egyptians, and the people of other eastern nations. The coccus ilicis is one of these, still found in the Levant, Greece, Palestine, Persia, etc, on a species of oak, in which countries it is employed as it was before the time of Moses. It has long been known by the name of kermes, which came from the Arabs, and signifies red dye. Beckmann conceives that the ancients obtained a finer color from these insects than from Tyrian purples, and its introduction among the Romans caused the use of the latter to be abandoned. The name cochineal, which Beckmann suggests is the diminutive of the Spaniards for coccus, is limited to that species which came to the notice of Europeans soon after the conquest of Mexico. The Spaniards found it in high estimation among the natives, who "took infinite pains to rear the insect on plantations of the cactus; and it formed one of the staple tributes to the crown from certain districts." The Mexican coccus was soon introduced into Europe, where its superior quality was immediately appreciated.
Even the live insects were imported, and plantations of cactus were cultivated for their nourishment. The French and Spanish kermes, which at that time was in high repute, disappeared and was soon entirely forgotten. In the family coccidm the insects have the form of oval or rounded scales, which cover the stems, branches, and sometimes the leaves of plants. The males, winged, pass through the usual changes, but the females increase only in size, always retaining the scale-like form. - The coccus cacti is a small insect with the body wrinkled transversely; its abdomen of a deep mulberry color, and bristly in the posterior part; the legs are short and black, the antennas subulate and about one third the length of the body. The male has two erect wings, the female none. In Mexico they are reared chiefly in the state of Oajaca, those of the district of Mestique being considered the best insects. There are plantations of the nopal (opuntia cochincllifera) upon which they feed, the insects being tended with care equal to that ordinarily bestowed upon silkworms. Before the rainy season sets in, branches of the nopal covered with insects are cut off and brought under shelter to protect them from the weather.
At the close of the wet season, about the middle of October, the plantations are stocked from these supplies by suspending little nests made of some soft woody fibre, each containing eight or ten females, upon the spines of the nopal. The insects, warmed by the sun, soon emerge and lay their eggs, each female producing more than 1,000 young. These spread rapidly over the plants, and as the young females become impregnated they attach themselves to the leaves and swell to great size, presenting the appearance more of vegetable excrescences than of animated creatures. In this condition they are gathered for the cochineal. The males, which are few in number, not more than one to 100 or 200 females, are of no value for this purpose. The females are picked off with a blunt knife, the first crop about the middle of December, and subsequently several more of as many successive generations, the last being in May. A laborer can pick off only about enough to make two ounces of cochineal in a day. Those taken off full of young lose about two thirds of their weight in the process of drying, to which they are subjected as soon as they are killed, which is done ' either by dipping them in a basket into boiling water, or placing them in a hot oven or on plates of hot iron.
By the first method, usually considered the best, the insects turn to a brownish red color, losing a portion of the white powder with which they were previously loaded between the wrinkles of the body. In the oven they retain this, and their color is then gray. Those killed on hot iron turn black. Such is the origin of the different varieties known in our market as "silver grains1' and "black grains," and the "foxy" of the London market, the last being those killed by boiling water, though others ascribe it to the former being the female before laying her eggs, and the latter after she has parted from them. The quality of the cochineal is the same in both cases. When dried, the cochineal presents the form of grains, convex on one side and concave on the other, about one eighth of an inch in diameter, with the transverse wrinkles still visible. It is stated that it takes about 70,-000 insects to weigh a pound. In 1866 England imported 32,757 cwt., valued at £594,818, and exported 21,238 cwt., the annual consumption being about 12,000 cwt.; the price in 1870 was about 3s. per pound, a little more than half its former rate.
In 1871 the imports into the United States were 1,849,842 lbs., valued at $1,184,-255; of which 800,995 lbs. were from England, 736,573 lbs. from the United States of Colombia, 184,615 lbs. from Mexico, 100,675 lbs. from the West Indies, and 26,989 lbs. from other countries. An inferior quality of cochineal, called Sylvester, is collected from a wild species of cactus, though the insect is sometimes cultivated with the others. Cochineal insects are attacked and fed upon by birds, mice, and the larvae of other insects; the last named suck out their bodies, leaving only the skin. - Attempts have been made with some success to introduce the culture of cochineal into other countries. The English government at one time offered £6,000 to any one who would introduce it into India. The Spaniards, however, for a long time took every precaution to prevent the removal of the living insects from the country. They were introduced into the Canary islands about 1830, and after the failure of the grape in 1850 became the principal article of export.
In 1856 the exports were about 1,500,000 lbs.; in 1870, 6,000,000 lbs., valued on the spot at $3,200,000, most of which was sent directly to England. The French had succeeded in 1844 in establishing cochineal plantations in Algeria, and specimens have been produced from that country said to be superior to the best Mexican. The Dutch have also succeeded in producing large quantities of genuine cochineal in Java. A variety found in California has all the properties of the cochineal of Brazil and the southern part of Mexico, the only apparent difference being that the article found in California is a light pink, while that of other regions is a deep scarlet. - The coloring principle which causes cochineal to give a crimson color to its watery infusion has been separated by Dr. John, who gave it the name of cochiniline. It is a brilliant purple red color, very soluble in water and in alcohol, but insoluble in ether, obtained by macerating cochineal in ether, and treating the residue with alcohol, and evaporating. It is next to be purified from fatty matters which accompany it by dissolving again in alcohol, and adding a little sulphuric acid, which causes it to be precipitated in a few days.
The coloring matter is thrown down by different metallic salts, as those of zinc, bismuth, iron, nickel, tin, etc, and thus produces precipitates of various brilliant colors. By means of the chloride and nitrate of tin the bases of the splendid crimson and scarlet dyes are obtained, to which the great value of cochineal is chiefly owing. (See Carmine.) The best of the pigments called lakes are made by introducing freshly prepared gelatinous alumina into the decoction of cochineal. - The high price of cochineal has led to the substitution of other articles in dyeing, and lac and madder have superseded its employment to a great extent. Various articles are used in the adulteration of this substance. Powdered talc or carbonate of lead shaken in a bag with the insects adheres to their bodies, and increases their weight. Grains of a substance manufactured from colored dough have been prepared in France to imitate the dried insect.
1. Cochineal Insects on branch of Cactus. 2. Female Insect. 3. Male Insect.