Diagnosis. Very similar to ilicis, but male easily separated (also from most other species) by patches of brown androconial scales on hindwing upperside and forewing underside. Female cannot always be separated with certainty from ilicis, but usually heringella has some white scales in the region of the costal spot and also has slightly longer signa.
Description. Male. Forewing length 2.08 — 2.68 mm (2.43 ± 0.13, 19), wingspan 4.4 — 6.0 mm. Head: frontal tuft yellowish white to orange, in specimens from Cyprus fuscous on vertex; collar yellowish white. Antennae with 35 — 42 segments (38.4 ± 1.8, 15); scape with some brown scales in posterior distal corner. Thorax and forewings brown with some scattered white scales; medial dorsal spot white, some white scales along costa, not forming a distinct costal spot; underside of forewings with basally an elongate patch of brown (androconial) scales. Hindwing without hair-pencil, but with costal bristles; in basal half with a patch of brown (androconial) scales on upperside.
Female. Forewing length 2.24 — 2.60 mm (2.44 ± 0.20, 14), wingspan 4.6 — 5.8 mm. Antennal segments 27 — 32 (29.9 ± 1.4, 16). Without patches of brown scales on underside forewing or upperside hindwing.
Male genitaha. Capsule length 236—283 µm (252.9 ± 16.5, 9). Tegumen broad and rounded.
Gnathos with central element divided, distal part spatulate, basal part with serrate margin. Valva length 180 — 223 µm (209.0 ± 17.2, 9), inner margin almost straight or concave, tip prominent, slightly truncate. Aedeagus 257 — 300 µm (274.3 ± 16.5, 9) carinae single, bi- or trifurcate.
Female genitaha. T7 wJth a distinct row of 8 — 12 long setae along anterior margin of T8. T8 with two groups of 2 — 4 setae (7 in Cyprus specimen), without scales, but some scales present in specimen from Corsica; T8 narrow, with slightly sinuous posterior margin. Anal papillae with 8 — 15 setae. Vestibulum with vaginal sclerite, a dorsal spiculate pouch and a group of densely packed pectinations near the entrance of ductus spermathecae. Corpus bursae 580 — 715 µm, without pectinations; signa dissimilar, longest 407 — 583 µm (484 ± 73, 5), shortest 353—517 µm, (116 ± 73, 5), 4.0 — 4.7 x as long as wide. Ductus spermathecae with 2 indistinct convolutions.
Larva not examined.
Hostplants. Quercus ilex L., Q. alnifoliae Poech., ? Q. robur L. In northern Italy the species was frequently found in localities without any evergreen oaks (G. Baldizzone, personal communication), such as the Parco NR Capanne di Marcarolo. Since in Britain in an outbreak situation mines on Quercus robur have been seen, we assume that E. heringella can also feed on deciduous Quercus.
Leafmines cannot be separated from other related gallery miners, in its distribution area mostly E. haraldi and pseudoilicis.
Widespread in Eastern Mediterranean, from Cyprus westwards to Corsica and southeastern France (Alpes Maritimes), recently recorded as invasive insect from Great Britain: Langmaid and Young 2003; Prichard 2005; Vickery 2004; Palmer 2008; Sims 2008. Records for France: Van Nieukerken et al. 2006; Greece: Laštůvka and Laštůvka 1998. Here new for Sardinia and tentatively recorded for Tunisia on the basis of two females.
Univoltine, larvae from November to April, adults May (April?) to July.