Leaf-mine: The mine in Luzula pilosa is rarely at the leaf-tip, being usually about halfway down the leaf blade and well clear of the winter/pring dieback. The autumn mine typically consists of a long stright slended gallery folloowing one of the veims. The mine is no wider than the larva and the frass is scattered towards or away from the leaf-tip. In spring the mine is contined as a broad elongated gallery with frass irregularly placed. Pupation occurs on the upper surface of a leaf and is anchored by a silk girdle (Bland and Knill-Jones, 1988).

From autumn till early spring the larva makes a quite narrow corridor with a total length of 12-16 cm, essentually running parallel to the leaf venation; the corridor may change direction 2-3 times. Generally the corridor lies about halfway the length of the leaf. In March-April this gallery abruptly gives way to an elongate blotch, that generally obliterates the original gallery. The larva may leave its mine and restart elsewhere by making a lower-surface opening in a new leaf, not far from the leaf-tip. Pupation external (Bladmineerders van Europa).

Larva: The larva has a black head and prothoracic plates with a pink body and narrow creamy nid-dorsal line and a more diffuse creamy line along the spiracles. The intensity of the pink varies considerably (Bland and Knill-Jones, 1988).

Body more or less intensely pink, with three cream-coloured length lines; head and prothoracic plate black (Bladmineerders van Europa).

Pupa: See Patocka (1999a), Patocka and Turcáni (2005a) (Bladmineerders van Europa).

Adult: Not illustrated in UKMoths (check for update). The genitalia are not illustrated by the Lepidoptera Dissection Group (check for update).

Hosts in Britain:

Hosts elsewhere:

Time of year - larvae: Autumn to April-June of the following year (Bladmineerders van Europa).

Time of year - adults: Unknown.

Distribution in Great Britain and Ireland: Britain including East Norfolk, East Ross, Forfar, Kincardine, North Devon and South Wiltshire ( NBN Gateway, as Biselachista trapeziella - 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).

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, Finland, French mainland, Germany, Italian mainland, Latvia, Norwegian mainland, Poland, Slovakia, Sweden and Switzerland (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.