Cockroaches have rather flat bodies. This enables them to run under doors and squeeze into tight cracks. The body of a cockroach is oval-shaped. Cockroaches develop in a process called gradual metamorphosis. This means that the immatures, called nymphs, look very similar to adults.
Like all other insects, cockroaches have three body segments. The segments are head, thorax, and abdomen. The front segment is the head.
When they are viewed from above, the heads of cockroaches are almost completely hidden. The plate that covers the head is called the pronotum. Scientists use the markings on the pronotum to help identify cockroaches.
Cockroaches have long antennae. Among other things, they use the antennae to guide them along walls and around corners as they walk at night. Cockroaches also use their antennae as hearing and smell receptors.
Cockroaches have compound eyes. Scientists think that cockroaches can see a different part of the spectrum. For example, they do not see red, but they can see ultraviolet.
Cockroaches have chewing mouthparts. They are scavengers and will eat almost anything that provides nutrition. They will choose good things if there is a choice, but the first goal is to eat as quickly as possible and get out of sight.
The midsection of the cockroach body is called the thorax. This is the segment of the body that provides movement. The legs and wings are attached to the thorax.
Cockroaches have very long legs that look like they are covered with spines. Many cockroaches are fast runners. Scientists have found that the American cockroach can pick up its first four legs and run on the back pair of legs. In this manner, it is able to run faster than 3 miles per hour or 50 body lengths per second.
Not all cockroaches have wings. Cockroaches that have wings develop them during the nymph stage. Each time the nymph molts, the wings are a little more developed.
Some cockroaches, like the male American roach, have wings that are longer than its body. This roach can fly and when its wings are folded, it looks longer than it really is. Some cockroaches, like the German roach, have wings but do not fly. In some species, like the brownbanded, only the males have wings. Others, like the male and female Oriental roach, have only wing pads, or stubs.
The body segment at the back of the body is called the abdomen. This is the segment that contains the vital organs. At the back of the abdomen, many cockroaches have two sensory receptors called cerci. Scientists think that the cockroaches use the cerci to detect changes in air currents. This helps them escape from predators.
Female cockroaches produce eggs in a capsule called an ootheca. The ootheca emerges at the back of the abdomen. Some, like the German roach, keep the ootheca attached to their body until the eggs are ready to hatch. Others drop the ootheca or attach it in a safe place.