Thysanura is the now deprecated name of what for over a century was recognised as an order in the class Insecta. Members of the order shared several characterisics, such as of having three long caudal filaments, the lateral ones being the cerci, while the one between is a medial cerciform appendage, specifically an epiproct. They also are totally wingless and have bodies covered with fine scales, rather like the scales of the practically unrelated Lepidoptera. Until the mid twentieth century the order Thysanura included the suborder Archaeognatha, but since then the Archaeognatha have been raised to the status of an independent order in their own right. The name of the sole remaining suborder was the Zygentoma, encompassing the silverfish and firebrats. The Zygentoma too, were raised to full order status.
Once the Zygentoma were given full order status, the term "Thysanura" became redundant as an order name, but the momentum of nearly two centuries of nomenclature has kept the name Thysanura in common use and in much published material.
The name Thysanura is derived from the Greek θυσάνος, thysanos for fringe, tassel, bristle and οὐρά, oura for tail, a reference to the three fanned out caudal filaments.
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