Apterygota is a subclass of insects that are characterized by their lack of wings. This group includes primitive insects such as silverfish and bristletails. They are among the most ancient forms of insects, having existed for over 400 million years. Apterygota typically have a flattened body and long antennae, and they are often found in damp environments. These insects undergo a simple life cycle known as ametabolous development, where they grow through a series of molts without undergoing a distinct metamorphosis. Apterygota primarily feed on organic matter, such as decaying plant material, and play an important role in the ecosystem by aiding in decomposition.