Looks Can Kill
All Medusan units employ a basic gray color scheme, with trim colors based on the squadron. The Command and Support Squadron employs gold trim, while Hydra Squadron uses red, and Basilisk Squadron uses blue.
Per Mercenaries Supplemental 2, page 49.
The Medusans' insignia is a skull surmounted by a writhing mass of snakes in place of hair. The Hydra Assault Squadron's squadron insignia is a fearsome seven-headed serpent. The Basilisk â€“ a mighty serpent â€“ serves as the Basilisk Assault Squadron's insignia. Per FM: Mercenaries Supplemental II, pages 49-51.
Invader, Union, and Overlord, Mercenaries Supplemental 2 (color plates)