An endangered Red Data Book species, in brackish marshes in south-eastern England, a priority species under the UK Biodiversity Action Plan. The two known breeding areas are both in the south-east region. It occurs in the Romney Marsh/Rye area on the border of East Sussex and Kent and on the banks of the Medway between Maidstone and Rochester in Kent. Unlikely to be recorded in Hampshire or on the Isle of Wight. Wingspan 40-46 mm. Larva feeds on Marsh-mallow, over-wintering as an egg.