Mesozoic insects

Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic. Females typically have a special ovipositor for inserting eggs into hosts or places that are otherwise inaccessible. This ovipositor is often modified into a stinger. The young develop through holometabolism (complete metamorphosis)—that is, they have a wormlike larval stage and an inactive pupal stage before they reach adulthood.

The silverfish (Lepisma saccharinum) is a species of small, primitive, wingless insect in the order Zygentoma (formerly Thysanura). Its common name derives from the insect's silvery light grey colour, combined with the fish-like appearance of its movements. The scientific name (L. saccharinum) indicates that the silverfish's diet consists of carbohydrates such as sugar or starches. While the common name silverfish is used throughout the global literature to refer to various species of Zygentoma, the Entomological Society of America restricts use of the term solely for Lepisma saccharinum.

Hymenopterida is a superorder of holometabolous (metamorphosing) insects. As originally circumscribed, it included Hymenoptera and the orders in Panorpida (Mecoptera, Siphonaptera, Diptera, Trichoptera and Lepidoptera). However, more recent studies find Hymenoptera as sister to the other members of Holometabola and the superorder is restricted to Hymenoptera.