Diagnosis. Scandinavian specimens of luteella can normally be separated from the other species of the betulicola group by the more constrasting forewing colour pattern: the brownish proximal part and the dark purplish distal part and by the triangular fascia which tapers strongly towards costa and usually does not reach costa - the latter character is particularly useful in recognizing specimens of luteella with yellow head. The male genitalia are very similar to those of S. glutinosae but differ by the deeper bilobed vinculum and the concave hind margin of uncus.
Male. Wingspan: 4.7-5.2 mm. Head: frontal tuft pale ochreous to yellowish brown or dark fuscous (in Scandinavia usually yellow); collar and scape white or yellowish white; antenna approximately half length of forewing or longer, grey-brown. Forewing: area proximal to fascia yellowish brown to bronzy fuscous, sometimes faintly tinged with olive-green or purple; in central Europe usually bronzy fuscous; fascia postmedial, yellowish, sometimes ill-defined and normally narrow or obscure at costa, broadest at dorsum; distal to fascia dark purple fuscous; terminal cilia concolorous but with paler tips. Hindwing: pale greyish brown. Abdomen brownish black with slightly purple tinge. Female. Wingspan: 4.7-5.2 mm. Head: antenna slightly shorter than half length of forewing; flagellum pale grey.
Male genitalia. Vinculum broad, with very deep, U-shaped excavation; lateral corners broad and rounded. Uncus with posterior corners pointed outwards, hind margin emarginate. Gnathos with long horns and narrow transverse bar. Tegumen narrow. Transtilla narrow, bilobed, without distinct sublateral processes. Aedeagus very small.
Female genitalia. Signa varying in size but usually large (sometimes covering almost entire bursae). Pectinations absent or, if present, fine and indistinct.
Host plants: Betula pendula, B. pubescens and rarely B. nana. Egg: on lower surface of leaf, close to a rib. Larva: pale yellow to almost colourless, with green intestine and yellow-brown head. Mine: short, 3-4 cm long; mine relatively broad and strongly contorted at the beginning, with 2-3 coils; first half green, in lower layer of leaf, and usually following a vein. Frass in a thick irregular line occupying one third to half width of the mine, more in the first half. The mines are found later in the autumn than those of the other birch-feeding Stigmella, often in 'green islands' in yellow leaves. Cocoon: pale red-brown.
Widely distributed in Denmark, Sweden and Finland. Known from southern Norway. - Its range includes large parts of Europe from Ireland to western USSR, northern Italy and Yugoslavia, probably also in east Palaearctic.
Voltinism: probably only one generation per year. The adults fly during the spring and early summer but single specimens are found until the end of July, the larvae are found during the late summer and mainly throughout the autumn in northwest Europe, being the latest Betula feeding species of Stigmella.
Description based on Johansson and Nielsen (1990)