Definition
Thysanura is an outdated taxonomic term, formerly an order of insects that included silverfish and bristletails. These are wingless insects characterized by their elongated bodies, three long tail-like appendages, and scale-covered bodies. They're often found in dark, humid places like bathrooms and basements. This classification has been replaced by more modern taxonomy. Think of them as the ancient survivors of the insect world. They have changed little over millions of years.