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a subfamily of beetles of the family Chrysomelidae. The elongate body is approximately 10 mm in length (sometimes up to 15 mm). The brightly colored beetles are found primarily in the temperate zone of the northern hemisphere. They live on aquatic plants, feeding on the leaves. The larvae live on the submerged stalks and roots of aquatic plants. They obtain air from the respiratory vessels of the underwater portions of the plants; however, they are also capable of cutaneous respiration of the oxygen dissolved in the water. Of the more than 120 species of Donaciinae, as many as 50 are encountered in the USSR.