The Margarodidae or ground pearls are a family of scale insects within the superfamily Coccoidea. Members of the family include the Polish cochineal and Armenian cochineal and the original ground pearl genus, Margarodes. Beginning in 1880, a number of distinct subfamilies were recognized, with the giant coccids being the first. Although Maskell proposed a new family, many continued to regard the monophlebids as a mere subfamily for many years, and the Margarodidae classification continued to be polyphyletic through the 20th Century. Since then, taking the advice of Koteja several subfamilies and tribes have been elevated into their own families such as Matsucoccidae and Xylococcidae. The pared-down family of Margarodidae is monophyletic.

Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than the superfamily Coccoidea due to taxonomic uncertainties. Adult females typically have soft bodies and no limbs, and are concealed underneath domed scales, extruding quantities of wax for protection. Some species are hermaphroditic, with a combined ovotestis instead of separate ovaries and testes. Males, in the species where they occur, have legs and sometimes wings, and resemble small flies. Scale insects are herbivores, piercing plant tissues with their mouthparts and remaining in one place, feeding on sap. The excess fluid they imbibe is secreted as honeydew on which sooty mold tends to grow. The insects often have a mutualistic relationship with ants, which feed on the honeydew and protect them from predators. There are about 8,000 described species.