Leaf-mine: Corridor widening while descending from the tip of the leaf. The mine is unusual because the sides are very irregularly scalloped out. Moreover, the mine is not evenly transparent, but rather yellowish green and motly, because the larva leaves patches of parenchyma uneaten, and does not feed full depth. Frass in a few irregular, interrupted length lines. Often 2-3 larvae in a mine. The larvae hibernate in the centre of the mine; after winter they leave their mine and pupate (Bladmineerders van Europa).

Larva: Bone coloured. Pronotum, prosternum and anal shield have chitin structures of a characteristic shape (Steuer, 1976a) (Bladmineerders van Europa).

Pupa: Details unknown.

Adult: The adult is illustrated in UKMoths. The male genitalia, but not the female (check for update) are illustrated by the Lepidoptera Dissection group.

Comments: Festuca gigantea is treated as Schedonorus gigantea (Giant Fescue) by Stace (2010).

Hosts in Britain: Various grasses (UKMoths). The male genitalia, but not the female genitalia (check for update), are illustrated by the Lepidoptera Dissection Group.

Hosts elsewhere:

Time of year - larvae: October until about April (Bladmineerders van Europa).

Time of year - adults: The adult moths emerge in a single generation from late April to June in the south, and somewhat later in the north, from June to July. There may occasionally be the emergence of a second generation in the south (UKMoths).

Distribution in Great Britain and Ireland: Common throughout woodland clearings in Britain (UKMoths) including Bedfordshire, Caernarvonshire, Cambridgeshire, Cheshire, Derbyshire, East Norfolk, East Suffolk, Kincardine, Merionethshire, North Aberdeen, Shropshire, South Aberdeen, South Lancaster, South Wiltshire, South-west Yorkshire, Stafford, Warwickshire, West Norfolk and West Suffolk (NBN Gateway - N.B. includes Watsonian Vice Counties having publicly available records that fall within or overlap the vice county border at 10km resolution or better i.e. a record for a vice county may relate to an adjacent vice county - for included datasets see NBN Grid map below) and Northern Ireland (Karsholt and van Nieukerken in Fauna Europaea).

Also recorded in the Republic of Ireland (Karsholt and van Nieukerken in Fauna Europaea).

NBN Grid map: Note that not all datasets on the NBN Gateway may be available on the map below. If you are an NBN Gateway registered user you can request access for missing datasets via the link 'Open interactive map in new window' below.

Distribution elsewhere: Widespread in continental Europe including Austria, Belgium, Czech Republic, Danish mainland, Estonia, Finland, French mainland, Germany, Hungary, Italian mainland, Latvia, Norwegian mainland, Poland, Romania, Russia - North and Northwest, Slovakia, Sweden, Switzerland and The Netherlands (Karsholt and van Nieukerken in Fauna Europaea).

NBN interactive distribution map(s) of known host species in Great Britain and Ireland and elsewhere:

Parasitoids in Britain and elsewhere: Unknown.