Last modified: April 23, 2019, 12:44 p.m.
Not very common, mainly observed in Flanders and from the mine only. Adults are rarely observed.
Forewing greyish with a row of small, inconspicuous, whitish striae along the costa; some brown spots near the inner margin. Identification very difficult without knowledge of the larval host plant, because of the resemblance with the other Parnornix species; study of the genitalia is necessary.
The first instar lives in a short, inconspicuous, gallery on the underside of the mine, only visible because of the reddish brown frass line; the gallery soon turns into a brownish blotch. The blackish frass is contained in a corner of the mine. Because the caterpillar spins only few silk, the mine remains almost flat.
See also gracillariidae.net and bladmineerders.be.
When the caterpillar leaves the mine, it folds the margin of a leaf tip downwards and fastens it wilk white silken threads. It continues feeding from within this fold, which after a while turns completely brown.
Pupation in the fold, among other fallen leaves on the ground during autumn. The species hibernates in the pupal stage.
The adults rest during daytime between the foliage or in cracks on the tree trunk. They become active towards dusk and at night. They come to light.
Two generations a year: May–June and July–August.
The species lives monophagously on Fagus sylvatica.
Beech forests, gardens and parks with individual Fagus trees.