Cockroaches are flat, nocturnal insects that hide in cracks and crevices during the day. Under good conditions, cockroaches can reproduce rapidly. Female cockroaches place 18 to 30 eggs within a protective covering or egg case called an ootheca, which is later deposited in a protected location. A single female may produce 4 to 20 oothecae during her lifetime. The ootheca provides protection for eggs as they develop prior to hatching and emergence of young cockroaches. Cockroaches or their ootheca can be the source of a new infestation, and both are transported easily in grocery sacks, boxes, animal feed sacks or other similar containers.