The Phasmatodea (sometimes called Phasmida or Phasmatoptera) are an order of insects, whose members are variously known as stick insects (in Europe and Australasia), stick-bugs or walking sticks (in the United States and Canada), phasmids, ghost insects and leaf insects (generally the family Phylliidae). The ordinal name is derived from the Ancient Greek φάσμα phasma, meaning an apparition or phantom, and refers to the resemblance of many species to sticks or leaves.