Last modified: April 23, 2019, 12:44 p.m.
This species is not very common in Belgium.
The egg is nipple-shaped.
The yellowish brown larva has a black head and prothoracic plate.
The black case is pistol-shaped, black, laterally compressed at the bi-valved end measures circa 7 mm when it reaches its maximal size. The mouth angle is 30–45°.
See also bladmineerders.be.
The eggs are deposited at the underside of the leaf. The young larvae make, before overwintering, small mines. From mid April they resume their activities but, by then, small leaves are eaten starting from the leaf-edge. Eventually, window feeding is done, usually at the bottom of the sheet. They are full grown by the end of May or early June. Pupation takes place inside the case, mostly at the upper side of a leaf or, more seldom, against a twig.
The adults fly in June and July.
This species feeds monophagously on Betula.