Eupelmidae
Eupelmidae is a family of parasitic wasps in the superfamily Chalcidoidea. The group is apparently polyphyletic, though the different subfamilies may each be monophyletic, and may be elevated to family status in the near future. As presently defined, there are over 905 described species in 45 genera. The larvae of the majority are primary parasitoids, commonly on beetle larvae, though many other hosts are attacked, including spiders, and details of the life history can be variable (e.g., some attack eggs and others are hyperparasites). They are found throughout the world in virtually all habitats. They are somewhat variable in  appearance, though a fair number of species are relatively easy to separate from other Chalcidoidea by the possession of a medially concave mesonotum. They also have the unusual tendency to arch the body strongly upwards when dead, with the head and metasoma often nearly touching above the thorax.