The Evanioidea are a small

hymenoptera Hymenoptera is a large order (biology), order of insects, comprising the sawfly, 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 Par ...

n superfamily that includes three families, two of which (

Aulacidae The Aulacidae are a small, cosmopolitan family of wasps, with two extant genera containing some 200 known species. They are primarily endoparasitoids of wood wasps (Xiphydriidae) and xylophagous beetles (Cerambycidae and Buprestidae). They are c ...

and

Gasteruptiidae The Gasteruptiidae are one of the more distinctive families among the apocritan wasps, with surprisingly little variation in appearance for a group that contains around 500 species in two subfamilies ( Gasteruptiinae and Hyptiogastrinae) and wi ...

) are much more closely related to one another than they are to the remaining family,

Evaniidae Evaniidae is a family of parasitoid wasps also known as ensign wasps, nightshade wasps, hatchet wasps, or cockroach egg parasitoid wasps. They number around 20 extant genera containing over 400 described species, and are found all over the world e ...

. The rich fossil record, however, helps fill in the gaps between these lineages. They all share the trait of having the

metasoma The metasoma is the posterior part of the body, or tagma, of arthropods whose body is composed of three parts, the other two being the prosoma and the mesosoma. In insects, it contains most of the digestive tract, respiratory system, and circula ...

attached very high above the hind coxae on the

propodeum The propodeum or propodium is the first abdominal segment in Apocrita Hymenoptera (wasps, bees and ants). It is fused with the thorax to form the mesosoma. It is a single large sclerite, not subdivided, and bears a pair of spiracles. It is strongl ...

. It is a poorly known group as a whole, with some 1100 known species in total, and a great many species are still undescribed. While each of the three families differs in biology, within each family, they are remarkably uniform in appearance and habits. The oldest records of the group date to the

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

, and were diverse from the Middle Jurassic to mid

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

, however, during the mid-Cretaceous they were overtaken in diversity by the

Ichneumonoidea The superfamily Ichneumonoidea contains one extinct and three extant families, including the two largest families within Hymenoptera: Ichneumonidae and Braconidae. The group is thought to contain as many as 100,000 species, many of which have not ...

, and since the end of the Cretaceous have a relatively scant fossil record.

References

External links

Tree of Life Evanioidea
Apocrita superfamilies {{Apocrita-stub