Diagnosis. Similar to S. sakhalinella and S. luteella but fascia often more distinct and always reaching costa; frontal tuft normally paler than in the continental form of luteella. The male genitalia differ from those of S. betulicola in having the slightly longer vinculum, larger uncus with outwardly pointing corners and narrower distal half of valva with many long setae; it differs from the other species of the betulicola group in having shorter vinculum and by presence of distinct sublateral processes. The female genitalia can be recognized by the dense cover of fine folds encircling the signa and covering most of the bursa.
Male. Wingspan: 4.5-5.2 mm. Head: frontal tuft ochreous; collar and scape yellowish white; antenna pale grey-brown, half length of forewing or slightly longer. Forewing area proximal to fascia bronzy grey-brown, sometimes with faint purple tinge; fascia pale yellow, faintly shining, width of fascia variable sometimes very narrow but almost always wider at dorsum; distal to fascia purplish grey-brown to purplish fuscous; terminal cilia grey-brown, shading into white at tip. Hindwing and cilia pale grey. Abdomen shining grey to grey-brown.
Female. Wingspan: 4.5-5 mm. Antenna half length of forewing or slightly shorter, otherwise similar to male.
Male genitalia. Vinculum relatively short with moderately deep anterior emargination. Uncus with almost straight posterior margin and blunt, outwardly pointing corners. Tegumen broad, slightly to distinctly narrowed in middle. Gnathos with long horns. Valva arcuate, distal half narrow with many long setae. Transtilla slightly narrowed in middle, sublateral processes broad and distinct. Juxta small, triangular. Aedeagus very small. Female genitalia. Very similar to those of S. sakhalinella. Corpus bursae ovoid with two ovate signa of approximately the same size and position, corpus completely covered with fine pectinations and folds. Accessory sac very small.
Host plants: Salix alba, S. babylonica and S. triandra. Egg: in any part of the leaf, upper or underside. Larva: yellow with pale brownish head, feeding with venter upwards. Mine: first third or half of mine usually in leaf underside, often following a vein or midrib and hardly visible, second half easily visible, often doubling back along the midrib or meandering in one half of the leaf; frass deposited as broad central line occupying at least half the width of the mine. Mine narrower and straighter than other Salix mines. Cocoon: varying from pale yellowish brown to dark red-brown.
Not in Denmark or Fennoscandia. - A mainly south-east European species distributed in Greece, Hungary, northern Italy, Austria, and recently found in Poland, where the characteristic mine was collected by Buszko (in litt.).
Voltinism: bivoltine, mines from mid July to beginning of August and from the end of September to mid October. Adults from beginning of April (probably not under natural conditions) to beginning of July and from the end of July to mid August.
Description based on Johansson and Nielsen (1990)