flower bug, (family Anthocoridae), any of at least 400 species of small insects in thetrue bug order, Heteroptera, that are black with white markings and are usually found on flowers, under loose bark, or in leaflitter. Flower bugs range in size from 2 to 5 mm (0.08 to 0.2 inch) in length. Their eggs are deposited in plant tissue, and the adults pass the winter in piles of plant debris. Flower bugs differ from most heteropterans because they have a well-defined embolium (a section of the wing). Theinsidious flower bug,Orius insidiosus, is a common North American species that preys on thegrape phylloxera and thechinch bug. In general, most of the species feed on aphids and aphid eggs. However, several species, such as the larger pirate bug (Lycotcoris campestris), suck human blood.