Flatterulme
The larvae feed on "Ulmus campestris" and "Ulmus laevis". They mine the leaves of their host plant. The mine consists of a narrow, contorted corridor with a broad, but often long interrupted frass line, which widens into an oval blotch that often partly obliterates the initial corridor. The frass in the blotch is black and concentrated in the basal part and along the sides.