Definition of Polish cochineal

Polish cochineal (Porphyrophora polonica), also known as Polish carmine scales, is a scale insect formerly used to produce a crimson dye of the same name, colloquially known as Saint John's blood. The larvae of P. polonica are sessile parasites living on the roots of various herbs – especially those of the  perennial knawel – growing on the sandy soils of  Central Europe and other parts of Eurasia. Before the development of aniline, alizarin and other synthetic dyes, the insect was of great economic importance, although this was declining after the introduction of Mexican cochineal to Europe in the 16th century.