There are many different species of cockroaches, but the most common and most economically important is the German Cockroach. It is the one most often found in homes, apartments, motels, restaurants, etc. They tend to feed at night and during the day they spend their time in cracks, crevices, and voids. If they are seen in any large numbers during the day, it usually indicates a severe infestation. They are usually found in areas near food and water in buildings. If an apartment complex, motel, etc. is infested the entire structure must be treated because treating only one apartment, one room etc. may drive them into other areas of the struture. Cockroaches can contaminate food with their body parts, egg cases, and fecal material. This material is also associated with the rise of childhood asthma cases in this country.
Adult German Cockroach
Two dark parallel lines on the thorax are the key identifying markings.
German cockroach nymph, They go through 6 or 7 "instars" (molts) before becoming adults. They get larger with each one, but don't change their appearance until reaching adulthood.