All roaches belong to one of four families-blattellidae, blattidae, blaberidae and polyphagidae. Blattellidae includes black-brown-grey insects with well developed wings-this includes the common American, German and brown-banded roaches. Blattidae insects can be dark or light in colour depending on their species-for example, the oriental cockroach is brownish while a smokybrown cockroach is a mix of dark brown and grey. Blaberidae is another group including these larger types of roach as well as Australian and Madagascan species. Polyphagidae is a smaller group of insects that are more adapted to moist environments, but the full list includes about 70 types of roach