Stigmella lemniscella (Zeller, 1839)
Diagnosis. Males of lemniscella differ from all other Stigmella males in having the combination of black vertex, silvery fascia, and dark hindwings with long androconial scales along costa and dorsum. The female is externally similar to several species of the aurella group, S. alnetella and S. continuella. The male genitalia of lemniscella and S. continuella are very similar, but they can be separated by the V-shaped horns of the gnathos in lemniscella (horns parallel in continuella) and blunt distal spines in vesica in lemniscella (broad triangular in continuella). The female genitalia of lemniscella and continuella cannot be separated with certainty.
Male. Wingspan: 5.0-5.5 mm. Head: frontal tuft ochreous, vertex black; collar fuscous mixed with a few ochreous scales; scape white; posterior margin black; antenna approximately half length of forewing, bronze brown. Thorax shining greenish gold. Forewing: area proximal to fascia shining brownish gold; base of forewing, costa and an indistinct band before fascia slightly darker, more or less suffused with purple; fascia slightly oblique, shining silver; distal to fascia dark brownish purple to fuscous; underside of forewings bluish black; terminal cilia brown, shading into shining grey at tips. Hindwing: grey, covered with long, fuscous androconial scales, tip brownish; cilia grey, long black hair-scales along costa and dorsum extending over cilia to at most two thirds. Abdomen purplish fuscous with small yellowish anal tufts.
Female. Wingspan: 4.9-5.4 mm. Frontal tuft ochreous to orange; collar yellowish white; scape pale yellow; antenna slightly shorter than half length of forewing. Hindwing pale grey, slightly darker at tip; cilia pale grey. Abdomen grey brown; tip pointed, without anal tufts. Male genitalia. Vinculum with anterior margin deeply emarginate. Uncus small. Gnathos forming triangular medial plate with close-set, V-shaped horns. Valva with distal process and inner lobe short and blunt. Transtilla with long transverse bar and blunt sublateral processes. Aedeagus bottle-shaped, vesica with numerous spines; distal, weakly sclerotized spines scale-shaped and blunt. Manica sparsely spined. Female genitalia. See group diagnosis; cannot be separated from those of S. continuella.
Host plants: Ulmus spp. Egg: on either side of leaf. Larva: yellow. Mine : a long, sinuous gallery, almost completely filled with frass deposited in arches; length of mine varies with thickness of leaf. Autumn miners are often found in yellow areas of the leaf. Cocoon: brown.
Widely distributed in Denmark. In Sweden up to Vstm. Not in Norway; Grönlien's (1932) records cannot be verified. In south Finland. - British Isles, central and northern Europe.
Voltinism: two generations per year. Mines from late June to early July and from late September to mid October; adults in May-June and late July to early August.
Description based on Johansson and Nielsen (1990)
