Description: Wingspan 20-22mm. Males are larger than females. The forewings are distinctly rounded, pale greyish-white with dark veining. There is also a small dark discal spot on each wing, with a series of dark elongated spots and a chequered brown fringe. From the end of June until mid-August, occasionally later in some years.

World Distribution: Throughout northern Europe as far east as the Urals.

Irish Distribution: Common and widespread in southern counties. It was previously considered rare throughout Ireland, but in recent years (especially since the early 1990s) it has been discovered on many bogs and fens in north Armagh and Down. There are also recent records from Fivemiletown, Tyrone and Carganamuck and Crom Estate, Fermanagh.

Ecology: A small species associated with bogs and marshes and damp grassland. Given its small size and resemblance to a micro, it seems more likely that it has been overlooked in many sites rather than increasing its range. Increased fieldwork in the west may show that it is also more widespread here than previously thought. Adults are attracted to light in small numbers. The larvae feed on species of lichen growing on the branches of trees. It overwinters as a larva.

Key Identification Features:

• Small size
• Well-rounded forewings and dark-coloured discal spots on all wings.

Distribution Map from NBN: Thumatha senex at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Thumatha senex at iNaturalist World Species Observations database.