Flatterulme
The larvae feed on "Ulmus glabra", "Ulmus laevis" and "Ulmus minor". They mine the leaves of their host plant. The mine starts as a contorted gallery, filled with black frass. The mine continues as a straight corridor which is almost completely filled with frass. Older larvae live freely at the leaf underside, causing window feeding. Larvae can be found in July and from September to October. They are transparent yellowish. The species overwinters in the pupal stage.