The Ichneumon wasp was a type of wasp found on Earth. They belonged to the order Hymenoptera. (AUDIO: Divine Intervention) Their reproductive cycle involved laying their eggs in living caterpillars, which provided a food source for their grubs when they hatched. (AUDIO: Wirrn Dawn) More generally, they used their extra-long stingers to inject their eggs into the larvae of other insects. (AUDIO: Divine Intervention)
The Ichneumon wasp was the answer to a quiz question posed to the Eighth Doctor when he competed in You Either Know It or You Don't. He answered confidently without needing Jack Addison to repeat the question. (AUDIO: Divine Intervention)
In an alternate timeline, an Ichneumon wasp stung a battle-damaged Dalek in the year 2158, setting in motion the Mutant Phase - a chain of events that transformed the Daleks into Insectoid monsters. (AUDIO: The Mutant Phase)