Bees are flying insects closely related to wasps and ants. Bees are a monophyletic lineage within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila. There are slightly fewer than 20,000 known species of bee, in 9 recognised families,though many are un-described and the actual number is probably higher. They are found on every continent except Antarctica, in every habitat on the planet that contains flowering dicotyledons.