any of about 200 species of bugs (order Heteroptera) that are most abundant in the tropical Americas and Asia and that hide on flowers or plants from which they ambush their prey. When prey approaches closely enough, the ambush bug grasps it with its front legs. The upper section (tibia) of each foreleg has teethlike structures that mesh into similar structures on the lower, greatly thickened leg section (femur). Holding its victim in these pincers, the ambush bug inserts its short beak and sucks out the body fluids. Even though the ambush bug is small (usually less than 12 millimetres, or 0.5 inch), its prey may be as large as a bumblebee, wasp, or butterfly.
Learn more about ambush bug with a free trial on Britannica.com.