[5] In the UK, O. antiqua may be encountered in a variety of shrub-based habitats, including gardens, parks, open woodland, fens, hedgerows, heaths.

The female moth has vestigial wings and is flightless; it is light grey-brown (ochreous grey), has "shortly bipectinate" antennae, and a swollen abdomen.

[6][5] The compound eyes of the two sexes differ not only with regard to their size, number of facets and internal organization and ultrastructure, but also with regard to their sensitivity to ultraviolet radiation[7][8] The hairy caterpillar is spectacular, with "humps", "horns", and a "tail" in a combination of dark grey, red, and yellow.

Several hundred eggs are laid on the outside of the female's empty cocoon, usually attached to a host plant or something close by (e.g. fence, wall).

[5] In New Brunswick, adult males are attracted to pheromone traps set in commercial forests for white-marked tussock moth (O.

The female mates and lays her grey-yellow eggs in large numbers on her fine-meshed cocoon.

[6] Caterpillars are polyphagous and feed on a wide range of deciduous trees and shrubs, such as birch (Betula), Crataegus, lime (Tilia), Prunus, Quercus, Rubus, Salix, Tamarix, Vaccinium, Aeonium haworthii[10][9] or Delonix regia.