Wingspan 9-10 mm.
One of the larger species of Phyllonorycter, with a rather attractive 'striped' appearance, each stripe gradually fading from whitish through chestnut to black.
The larvae feed on alder (Alnus glutinosa), and create a long mine between two veins on the underside of the leaf. Often there are several to a leaf.
The moth is believed to have only a single generation, flying in July and August, though bred specimens will emerge in spring if kept indoors.