Any insect of the family Pseudococcidae (order Homoptera).
Not a true bug , the mealybug is covered by a white sticky powder resembling cornmeal. The females, about 0.4 in. (1 cm) long, and "crawlers" (the active young) cluster along the veins and undersides of leaves, especially of citrus trees and potted plants; the males are active two-winged fliers. Common species are the citrus mealybug ( Pseudococcus citri ) and the citrophilus mealybug ( P. gahani ).