Cockroaches are primitive insects that have gained a bad reputation because of a few species that infest structures. There are almost 70 species of cockroaches in the United States, only six or so species are considered important pests of homes and businesses. Immature cockroaches are called nymphs and differ slightly in appearance from the adult life stage. Adult female cockroaches produce unique egg cases called oothecae (oh oh THEE keh). The oothecae is dropped by the female before the young hatch, and are often found attached to walls, in drawers or other locations.