Small sap-sucking insects of the family Coccidae, to which scale insects also belong. Mealybugs are tiny but easily seen, flattened and slow-moving, with a whitish water-repellent coating like flour dusted over cobwebby hairs. They hide on the undersides of leaves, among sheathing leaf bases, and among plant roots, thriving best on plants grown indoors in very open potting mix. They are persistent and difficult to eradicate.