Diagnosis: females are externally almost inseparable from E. argyropeza, only the larger number of antennal segments (34 — 38 in klimeschi, 26 — 32 in argyropeza) being diagnostic. Female genitalia can be separated from argyropeza by the signa which are longer in klimeschi, at least always longer than the shortest signum of argyropeza. There is some resemblance to the species of E. albifasciella-complex, but the latter have the costal spot always nearer the wing base and lack the hair-pencil in the male. See key for differences with suberis.
Description.
Male. Forewing length 2.76-3.6 mm (3.09 ± 0.27, 12), wingspan 6.0—8.2 mm. Head: frontal tuft and collar yellowish orange. Antennae with 49 — 58 segments (52.8 ± 3.2, 13). Thorax and forewings blackish fuscous, slightly irrorate by lighter scale-bases; a medial dorsal and costal white spot, opposite, usually widely separate; dorsal spot sometimes extending along dorsal margin towards base. Hindwing with yellowish hair-pencil of 1/4—1/5 hindwing length.
Female. Forewing length 3.0 — 3.08 mm (3.05 ± 0.03, 5), wingspan 6.7 — 6.8 mm. Antennae with 34 — 38 segments (35.1 ± 1.3, 15).
Male genitalia. Capsule length 292—321 µm (307.7 ± 11.9, 5). Tegumen produced into a widely rounded pseuduncus. Gnathos with relatively long, triangular central element. Valva length 214—236 µm (226.3 ± 8.2, 5), widest at base, gradually narrowing into triangular tip, not demarcated from valva. Aedeagus 390—411 µm (405.4 ± 8.9, 5), very long and stout, markedly asymmetrical, posteriorly curved at right-hand side; with two pairs of prominent carinae: ventral pair at extreme posterior tip, basally connected, pointed, single; dorsolateral pair more anteriorly placed, longer than ventral carinae, strongly curved, dorsally connected, often with additional spine at base, which is larger in left process, asymmetrical.
Female genitalia. T7 without row of setae. T8 wide, trapezoid, with two lateral groups of scales and many setae (13 — 20 at least). Anal papillae with 9-11 setae. Vestibulum with vaginal sclerite, a dorsal spiculate pouch with many (more than 60) single, equally spaced, denticles; and a patch of densely packed pectinations near entrance of ductus spermathecae. Corpus bursae 660 — 715 µm, covered with small pectinations, partly in concentric bands around signa; signa almost similar, 373- 416 μm (394.3 ± 12.5, 8), 3.5- 4.4 x as long as wide. Ductus spermathecae with 2½ — 3 convolutions.
Larva. Pale yellow. Prothorax and segment 10 with sternites. Ventral plates absent.
Hostplant: Populus alba L., on saplings and large lobed leaves of young branches on trees. When sympatric with turbidella, always on different leaves, but sometimes on the same branch.
Mine. Egg on petiole, but almost impossible to find, between long hairs. Mine first straight gallery in petiole, causing it to swell. In final instar larva enters leaf, and makes blotch, usually not between veins, but incorporating vein or midrib in middle of mine; frass in two lateral lines, leaving passage for larva, which can withdraw itself in petiole. Sometimes the larva feeds so long in the petiole, that there is hardly a mine in the lamina. E. klimeschi does not cause such conspicuous green islands as the related species.
East and Southeast Europe, especially common in Danube bassin, from Western Germany to Rumania. Also recorded from Poland, Switzerland and northern Italy. Latvia: Savenkov 1989; Lithuania: Diškus 2003; Northern Germany: Roweck and Savenkov 2007; Bohemia: Laštůvka et al. 1992; Greece: Laštůvka and Laštůvka 1998, here recorded new for Bulgaria. Widespread in Europe, but not extending into western or northern Europe.
Life history. Univoltine. Larvae probably start feeding in summer, mature larvae can be found in October and November. Adults fly from May to July.
This taxonomic description is based on Van Nieukerken (1985) and Van Nieukerken et al (2010).