Cockroach

Common name for an order of insects, the most familiar of which are characterized by their oval shape, foul odor, and their status as household pests. About 4000 species are known worldwide; most inhabit the warm tropical regions of the globe. About 25 species have attained worldwide distribution due to accidental transport in commerce and their affinity for human habitation. Among these are most of the important pest species. Cockroaches are an ancient group, having changed little in appearance in 320 million years. Fossil records indicate that they were the predominant insects during the Carboniferous period 360 to 290 million years ago.  Learn more.