Leaf-miner and case-bearer: The case resembles that of C. violacea, but does not lie so flat again the leaf as this species (having a mouth angle of 30 to 50°). C. violacea also has a case which bulges in the middle, whereas in C. potentillae the case tapers towards the posterior (British leafminers).

Immediately after emergence the larva makes a full depth, quickly widening, corridor, with frass as small grains in a broad central band. Finally results a blotch of 2 x 5 mm, from which the youth case is cut. The fully developed case is a hairy, greyish brown to silver grey lobe case of about 1 cm long, with a clearly laterally compressed end; the mouth angle is about 90°. The case is difficult to separate from that of C. ochripennella (Bladmineerders van Europa).

Larva: The larva is illustrated in Bladmineerders van Europa.

Pupa: Details unknown.

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: September - May (British leafminers).

Time of year - adults: Unknown.

Distribution in Great Britain and Ireland: Britain including Northampton (Bozeat, Horn Wood) (British leafminers); Bedfordshire, Cambridgeshire, East Kent, East Suffolk, East Sussex, Herefordshire, Hertfordshire, Huntingdonshire, Isle Of Wight, Middlesex, North Hampshire, North Somerset, North Wiltshire, Northamptonshire, South Wiltshire, South-west Yorkshire, Surrey 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).

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 Belgium, Czech Republic, Danish mainland, Estonia, Finland, French mainland, ? Germany, Latvia, Norwegian mainland, Poland, Sweden 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.