Even the beneficial insect predators can inflict a painful bite if handled carelessly, resulting in an inflammation that can persist for a few days.
Many species are brownish or blackish, but some species are brightly colored.
The long, curved mouth parts form a beak which is carried beneath the body, with the tip fitting in a groove on the underside of the body. The middle of the abdomen is often widened, so the wings don't completely cover the width of the body. The female lays eggs in tight, upright clusters on leaves or in the soil. Nymphs resemble miniature, wingless adults. Most assassin bugs are generalist predators in gardens and fields.