Leaf-miner and case-bearer: Larva mines leaves (British leafminers). The larva builds a case from silk, resembling a razor shell in appearance. (UKMoths).

The full-grown case is 12 mm long and blackish-brown (British leafminers). The full grown larva lives in a blackish brown trivalved tubular silken case of about 8 mm.

The mouth angle is 0°-10°, causing the case to lay almost flat on the leaf (Bladmineerders van Europa).

Larva: Head and plates black. Body dull yellowish white; prothoracic plate large with median sulcus; mesothoracic plate consisting of four sclerites, the anterior pair dot-like and widely separared, the posterior pair subrtriangular and closely approximated; metathorax with two small, well-separated dorsal sclerites; thoracic segments with small lateral sclerites; an anal plate; four pairs of abdominal prolegs (Emmet at al., 1996a) (Bladmineerders van Europa).

Pupa: Details unknown.

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

Hosts in Britain:

Hosts elsewhere:

Time of year - larvae: August to October on Thistle, probably full-grown in autumn. September to October on Knapweed, feeding again from April until May or June (British leafminers).

Time of year - adults: The nocturnal adults fly in July and August and are attracted to light (UKMoths).

Distribution in Great Britain and Ireland: Occurring throughout most of the British Isles (UKMoths), including Bedfordshire, Caernarvonshire, Cambridgeshire, Cheshire, Denbighshire, Derbyshire, Durham, East Kent, East Norfolk, East Suffolk, East Sussex, Easterness, Flintshire, Glamorgan, Herefordshire,
Kincardine, Merionethshire, North Essex, North Hampshire, Pembrokeshire, Shropshire, South Aberdeen, South Wiltshire, Stafford, Surrey, West Cornwall, West Kent, West Norfolk, West Suffolk, Westmorland and Worcestershire (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 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, Croatia, Czech Republic, Danish mainland, Estonia, Finland, French mainland, Germany, Hungary, Italian mainland, Latvia, Lithuania, Norwegian mainland, Poland, Romania, Russia - Central and North, Slovakia, Sweden and Switzerland. Also recorded in the East Palaearctic (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.