The dried female of Coccus cacti, reared on Opuntia cochinillifera, and on other species of Opuntia. Mexico and Teneriffe.

Characters. - Ovate, plano-convex, about one-fifth of an inch (5 millimetres) long; wrinkled, of a purplish-grey or purplish-black colour; easily pulverisable, yielding a dark-red powder. Odour faint; taste slightly bitter.

Composition. - It contains a red colouring matter soluble in water, alcohol, or water of ammonia, slightly soluble in ether, insoluble in fixed and volatile oils.

Reactions. - On macerating cochineal in water, the insect swells up, but no insoluble powder should be separated. The greyish-white insect quickly becomes black when warmed before the fire.

Uses. - It has little medicinal value; it is used to give an attractive colour to various liquid preparations.