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DYEING AND CALICO PRINTING.

RED COLOURING MATTERS.

Cochineal, Kermes, Lac-lake, Gum-lac, Lac-dye.

The beautifully red substance known in commerce as cochineal is the driedbody of an insedt belonging to the order Homoptera and family of Coccidar.Although the discovery of the coal-tar colours has greatly diminished its con-sumption as a dye-ware, it is yet largely used for the production of crimsonand scarlet on wool and worsted. The red dye insedts inhabit various plants,and are distinguished as:—Genuine cochineal or Coccus cacti ; Coccus ilicis orkcrrncs ; Coccus lacca or Ficus ; Coccus cerificus and Coccus polonicus radicals.The family Coccus is divided into two groups, the one including the insedtsnot yielding any colour at all, while the other contains pigment, and these areespecially termed cochineal. These insedts are not larger than a small pea orlentil, and live upon those parts of certain plants which are exposed to air oron the roots. The insedts exhibit the shape of an oval shield, it being difficultto distinguish their head, thorax, and abdomen with the naked eye. As arule the females remain fixed to those parts of the plants to which they fastenthemselves with their suckers. The male insedts, however, move about, andsometimes are even provided with wings so as to be able to fly, but theyare only few in number, and do not make their appearance until an advancedperiod of the season. The females remain stationary after having laid eggs;and, dying soon after, their dried-up shell or shield serves as a shelter forthe eggs, whence has arisen the erroneous notion that they are vivipam.The natural term of life of the insedts is about a year; when fully developedthey appear as small hemispheres fixed by the base upon the surface of theplant; sometimes the shape is more ovoid; their colour varies from brownto red, or from violet to black.

The insedt known as cochineal lives upon a species of cadtus (the Cactusopuntia or Nopal , or also Opuntia coccinilifera ), a plant which grows in a wildstate in Mexico, but which for the sake of the insedt alluded to is cultivatedin gardens, being termed nopaleries. The flowers of this plant are small;the colour is red or yellow. The whole of the Cactacca seem to be rich inred colouring matter, whence has arisen the question whether the insedt reallyoriginates the red colouring matter, or only colledts and elaborates what ispre-existent in the plant. In Mexico and Central America two kinds ofcochineal are distinguished, viz., the Mesteque, or grana jina, home-grown orfine cochineal, principally grown in the Mexican Province of Mesteque andin Honduras, and the wild or forest cochineal, grana silvestra , colledted fromthe wild nopal. The former of these is more valuable than the latter, becauseit is far richer in colouring matter. The Mexican Indians cultivate the nopalplant sometimes in gardens near their dwelling houses, sometimes, also, atmore remote places towards the forests, where a spot is cleared by burningthe trees and properly tilling the soil so as to render it fit for the culture ofthe cadtus, which is reproduced from the shoots, and is fit for receiving andfeeding the insedts after a lapse of two years.

The harvesting of the insedts takes place before the setting in of the rainyseason, while the reproduction of the insedt is secured by cutting off from thenopal plant such young twigs as are covered with the young brood. Theseare placed under shelter from the stormy weather, and kept until the return of