Cockroaches are insects of the order Blattodea, which is derived from Latin for “an insect that shuns the light.” Like all insects, roaches have 6 legs. These legs come in pairs, and each pair is attached to a segment on the thorax. The front pair of legs are the shortest, while the hind legs are the longest. These strong back legs are the main source of propulsion and one of the reasons that cockroaches can run so fast, up to three miles per hour. Each leg of a cockroach also has spines. These spines were once believed to help provide sensory information, but now scientists know that they actually help roaches maneuver over difficult terrain. Roaches also have claws on their legs that can help them grip smooth surfaces.
American cockroach via Insects Unlocked