Last modified: Feb. 28, 2021, 11:32 a.m.
A common species wherever hawthorn is to be found throughout Belgium.
Head brown, mixed with white hairs; forewing ground colour brown; white pattern consisting of a basal line, sometimes finely edged with dark brown scales; a patch of whitish scales near the basis at the dorsum; four costal and three dorsal striae; a patch of dark brown scales in the apical area.
A small, tentiform mine on the underside of a leaf, most of the time at the margin of a leaf lobe; underside yellowish green with some longitudinal folds. Later on the mine becomes much contorted, sometimes even folding the leaf margin over the mine. Visible from the upperside as a brown, long patch. The frass is concentrated in the corner of the mine.
See also gracillariidae.net and bladmineerders.be.
The caterpillars of the summer generation do not construct a real cocoon, but just some flimsy spinning; those of the autumn generation construct a strong, yellowish brown cocoon. Pupa brown.
Pupation inside the tough cocoon, within the fallen leaves between leaf litter on the ground. The species hibernated in the pupal stage. After emergence of the adult, the pupal skin protrudes from the mine.
The adults fly in two generations a year: May and August–September.