The antennal flagellum comprises a group of segments at the end of the antennae, separated from the 5 basal penduncle segments by a distinct bend. The shape of the flagellum readily separates the three main woodlouse lineages.
- Diplocheta: Ligia and Ligidium have more than 10 bead-like articles (top left).
- Synocheta: the trichoniscid/styloniscid 'Pygmy Woodlice' have a cone tapering to point furnished with a terminal brush-like bristle (top right).
- Crinocheta: all other woodlice have either two or three elongated articles ending in a thin spine (bottom).
