The Orussidae or the parasitic wood wasps represent a small family of sawflies ("Symphyta").

[3] Contrary to other "Symphyta", the antennae insert near the lower edge of the compound eyes and close to the mandible.

The complete body is strongly sclerotized and bears a species-specific microstructure, which is relevant for species identification.

Orussidae and Stephanidae are the sole Hymenoptera in which the head bears a corona of erect teeth around the frontal ocelli.

The surface of the body is subdivided into distinct segments, each bearing a transverse row of 8−10 backward pointing spines.

[6] Numerous morphological and genetic studies indicate that the Orussidae form the sister taxon of the Apocrita, the wasps, bees, and ants.

Earlier, the Orussidae were sometimes put into a separate suborder, Idiogastra,[4] but today they are classified in their own superfamily, Orussoidea.

[12] The following list summarizes the genera and species and their gross distribution together with indications on identification keys: Twelve species of Orussidae are distributed in the United States and in Canada: In Great Britain, Orussus abietinus (Scopoli, 1763) was recorded by Stephens (1835)[31] upon two specimens caught by William Elford Leach in Darenth Wood and Devonshire around 1817.

Morice (1904)[32] recorded a more recent specimen taken at Hastings about 1880, but after re-examination this turned out to be Xiphydria prolongata (Geoffroy, 1785) (Xiphydriidae).

The oldest members of Orussoidea, the group containing Orussidae and its close relatives, are known from the Middle Jurassic Karabastau Formation of Kazakhstan.

Ophrynopus peritus Engel, 2008 was described from Dominican Amber,[37] Baltorussus velteni Schedl, 2011 from Baltic Amber,[16] Mesorussus taimyrensis Rasnitsyn, 1977 from the Late Cretaceous of Taimyr, Siberia[20] und Minyorussus luzzii Basibuyuk, Quicke & Rasnitsyn, 2000 from the Late Cretaceous of New Jersey.