[1] Like other parasitoid wasps, they were long placed in the "Parasitica", variously considered as an infraorder or an unranked clade, now known to be paraphyletic.

The name is derived from Latin 'ichneumon', from Ancient Greek ἰχνεύμων (ikhneúmōn, "tracker"), from ἴχνος (íkhnos, "track, footstep").

The superfamily is defined by fusion of the costal and radial veins of the fore wing, and almost all species have more than 11 antennal segments.

Ichneumonoidea contains a great deal of morphological diversity, with species ranging in size from 1 to 130 mm (0.039 to 5.118 in) long.

[3] Parasitoidism evolved only once in the Hymenoptera during the Permian, leading to a single clade which contains the Apocrita and the Orussoidea, but has been secondarily lost multiple times.

[10] Once inside, they oviposit within the caterpillars and escape the nest by releasing a chemical which causes the worker ants to fight each other rather than the intruding wasp.