Diagnosis. S. speciosa (Frey) (also on Acer) differs from aceris males by the presence of androconial scales on the hindwing and the greenish golden base of the forewing and in the females by the ferruginous head. S. crataegella also resembles aceris, but differs by usually smaller size and more brightly coloured forewings and, in the male, fuscous hindwings with short androconial scales along costa and dorsum. Male genitalia characterized by the combination of two distal processes on valva and the presence of a juxta. Female genitalia can be easily distinguished from species outside aceris group by the band of small spines near accessory sac and broad and blunt apophyses anteriores; the medial process on tergum VIII is present in only prunetorum and aceris among the northern European species.
Male. Wingspan: 3.7-4.9 mm. Head: frontal tuft dark fuscous; collar large, white; scape large, white; antenna shorter than half length of forewing. Forewing: area proximal to fascia golden fuscous with purple tinge near costa; fascia postmedial, silvery to pale golden, sometimes ill-defined or altogether absent; distal to fascia dark purplish brown often with a few dark blue scales; terminal cilia concolorous but paler at tips. Hindwing: pale grey. Female. Wingspan: 4.3-4.7 mm. Head: antenna distinctly less than half length of forewing. Otherwise similar to male.
Male genitalia. Vinculum with distinct lateral corners. Tegumen slightly wider than uncus. Uncus with hind margin slightly emarginate, margins well sclerotized. Gnathos with very long transverse bar, long horns and distinct anterior processes. Valva with narrowly pointed inner lobe, one short distal process at ventral side and one longer, arcuate distal process at dorsal side. Transtilla with long, outwardly-curved sublateral processes. Anterior margin of juxta with distinctly more sclerotized bar. Aedeagus approximately 1.3 to 1.5 times length of genital capsule; vesica with numerous close-set very small, blunt cornuti and pointed or bidentate spines. Female genitalia. Corpus bursae with band of small spines near accessory sac. Accessory sac small. Apophyses anteriores unusually broad and blunt, distinctly shorter than apophyses posteriores,
which are long and thin. Posterior margin of tergum VIII prolonged medially into pointed posterior process.
Host plants: Acer campestre, A. platanoides, A. tataricum; records from A. pseudoplatanus are probably based on misidentifications of S. speciosa. Egg: usually on underside of leaf, occasionally on upperside. Larva: green. Mine : long, narrow, sinuous gallery, filled with coiled greenish frass, rarely leaving narrow clear margins; in last centimetre of mine frass becomes darker and more or less linear; exit-hole on upperside. Fresh mines are hard to find, since frass and larva have approximately same colour as leaf; in withered mines frass becomes brown. Easy to separate from S. speciosa, which not only feeds on different species of Acer, but also its black frass leaves clear margins in speciosa. Cocoon: brownish.
In Denmark only from LFM; in eastern Sweden up to Gstr. In Norway only from Oslo and Drammen; absent from Finland. - Widespread and common in central and southern Europe, becoming more local towards the northwest. Very local in south England. Not found in The Netherlands and Belgium. Distribution shown by Schoorl et al. (1985).
Voltinism: bivoltine, trivoltine in southern Europe.
Description based on Johansson and Nielsen (1990)