Coleoptera is an order of insects whose members are commonly called beetles. The word "coleoptera" is from the Greek κολεός, koleos, "sheath"; and πτερόν, pteron, "wing", thus "sheathed wing". The order coleoptera contains more species then any other taxonomic order known to man. Almost 40% of all insects are beetles and about 25% of all life forms on Earth are beetles.