Any member of several families of sap-sucking insects (order Homoptera) whose bodies are covered by a waxy shell (the scale).
The eggs are protected by the female's body or scale or a waxy filamentous mass. Scale insects may attack any part of a plant, but each species is host-specific. Many species are serious plant pests; others have commercial value. The lac insect is used in a red dye and in shellac. Cochineal, a red dyestuff, consists of the dried, pulverized bodies of females of the species Dactylopius coccus . See also cottony-cushion scale , San Jose scale .