Last modified: Jan. 15, 2021, 11:41 a.m.
A not so common species in Belgium, but probably much more widespread.
The egg is deposited on the upperside, usually beside a rib.
The mine is a very contorted gallery which widens gradually, often forming a false blotch by merged 'S' turns, or even a true blotch. The frass lays central and is broken.
See also bladmineerders.be
The cocoon is brown to black.
The adults fly in one protracted generation during June and July.