The Latin feminine adjective, magna, meaning 'large', refers to a broad section of their legs (Basitarsus III) and long sting lancet in workers of this species.

Their face has a thick white hair with at least one full marking hidden underneath it.

[2] Sometimes workers have no marking at all on their face or thorax, like some populations found in Arnhem land in the Northern Territory.

The males are brightly marked, with cream bands on their face, thorax and legs.

The main differences with A. cassiae are their broad basitarsus III, long sting lancet and fine clypeus hair.