Optera

The Optera are a species of worm-like sapients native to the underground of planet Vortis. They are human-sized bipeds with a dorsal carapace, a pair of short legs and multiple short arms, large light-sensitive eyes and numerous head tendrils. They usually move around by hopping.

It is believed that they are descendants of Menoptera who have gone to the underground and had their wings atrophied. They are afraid of the surface world and all who hail from it; claiming that none of their kind who has adventured there has ever returned. As a result they act with hostility towards surface dwellers. They also worship the winged Menoptera as deities, although it appears they have stayed out of contact with them for a long time, since they initially fail to recognize a Menoptera who fell into their domain.

They also appear to have an animistic and/or personifying view of the world, as exemplified in their way of saying that they need to dig tunnels through a rock wall by claiming that the wall is "silent" and that they need to create "mouths" on it with their weapons to let it "speak more light".

When the Doctor and his companions (Vicki, Ian and Barbara) visited Vortis, the Optera were reunited with the Menoptera and assisted them in reclaiming the planet from the entity known as the Animus (which the Optera feared and referred to by the name Pwodarauk). With the help of the Menoptera they went to live on the surface again.