Diagnosis. Differs externally from S. regiella and S. mespilicola in having the combination of brown head, pale golden proximal half, and purple distal portion of forewing and the absence of androconial scales on hindwing of male. The male genitalia differ from those of regiella in having the distincly longer aedeagus, and valva with short distal process and narrower, pointed inner lobe. The female genitalia differ from those of regiella in having the globular accessory sac and larger corpus bursae.
Male. Wingspan: 4.5-4.8 mm. Head: frontal tuft dark brown; collar dark brown; scape white; antenna approximately half as long as forewing. Forewing: proximal half shining golden brown with purple tinge especially on costa; medial fascia broad, brassy or almost silvery, and ill-defined on inner margin; usually with a few golden brown scales on distal side of fascia; purple fuscous distal to fascia; terminal cilia concolorous but paler at tips. Hindwing: greyish brown. Abdomen fuscous. Female. Wingspan: 4.6-4.8 mm. Head: antenna slightly shorter than half length of forewing. Otherwise similar to male.
Male genitalia. Vinculum with long and pointed lateral corners. Uncus slightly bilobed with thickened posterior corners. Gnathos with short transverse bar, moderately long horns and long anterior processes. Valva with short distal process and narrow, pointed inner lobe; inner lobe extending beyond uncus and nearly as far posteriorly as distal process. Aedeagus approximately one and a half times length of genital capsule; some cornuti rather large and pointed. Female genitalia. Bursa copulatrix almost as long as abdomen. Accessory sac approximately one-third length of corpus, rounded, strongly folded; reticulate field small. Ductus spermathecae shorter than bursa copulatrix.
Host plants: only known with certainty from Sorbus torminalis. Egg: on leaf underside (Tutt, 1899). Larva: pale yellowish, head blackish. Mine (not examined): starts as straight, narrow gallery, which becomes wider and more contorted, almost forming blotch; linear frass throughout (Tutt, 1899).
Only known from the type-locality Tarrington in England and from two localities in Rheinland-Pfalz in West Germany. The distribution is mapped by Schoorl et al. (1985). All other records are probably misidentifications. There seem to be no recent records of the species.
Voltinism: in England univoltine, larvae feeding in July, adults emerging in May and June.
Description based on Johansson and Nielsen (1990)