Insects of Britain and Ireland: butterflies

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L. Watson and M. J. Dallwitz


Adults. Wingspan 45–55 mm (megera); the fringes conspicuously light-and-dark banded. Slender-bodied to medium built; short-bodied. The eyes hairy. Antennae reaching noticeably less than halfway to the wingtips, or reaching about halfway to the wingtips. The antennal clubs gradual-elongate to abrupt; curved to not curved; flattened (blunt, orange-tipped in L. maera and dark-tipped in L. megera). Labial palps ascending. Having only 4 fully developed legs. Fore-legs without a tibial epiphysis. Tibiae of middle legs 2-spurred. Posterior tibiae 2-spurred.

Forewings. Forewings apically blunt. The outer and hind margins angled at about 100–105 degrees. The outer margins slightly convexly curved to more or less straight; scalloped (but less emphatically so than the hindwings). Uppersides of the forewings tawny light brown, or dark brown, or orange-brown, or fuscous (depending on interpretation of “ground colour” versus markings); contrastingly dark-veined; eye-spotted. The eye-spots 1, or 1–2; posterior towards the apex. Uppersides of the forewings without a discal mark; extensively marked orange-brown, with several blotches in the disc, two or three towards the tornus, large subapical patch cut by dark veins, and a conspicuous dark, pale-centred eye-spot (sometimes double) near the apex.

Hindwings. Hindwings broadly rounded; with the outer margins scalloped. Uppersides of the hindwings dark brown, or fuscous; conspicuously dark-veined; conspicuously patterned. Uppersides of the hindwings eye-spotted. The eye-spots (2–)4; mid-posterior to near the tornus. Uppersides of the hindwings without a discal mark; colour-patterned like the forewings, but with the tawny component less extensive: dark fuscous, with two posterior orange-brown bands cut by dark veins, the outer containing 3 or 4 black, white-centred eye-spots.

Undersides of wings. Undersides of the forewings colour-patterned in pallid reflection of the uppersides; not dark-veined, or conspicuously dark-veined to not dark-veined; conspicuously eye-spotted. The eye-spots 1 (black, pale-ringed and white-centred); posterior towards the apex.

Undersides of the hindwings complexly patterned: pale with dark sinuous lines and marbling, and a series of small subterminal ocelli which are black with white centres and located each in an orange, brown-ringed spot; not dark-veined, or conspicuously dark-veined to not dark-veined; eye-spotted. The eye-spots 5–7; aligned posterior towards the apex to near the tornus. Undersides of the hindwings without a discal mark.

Wing venation. Forewings 12 veined (L. maera), or 13 veined; with basally dilated veins; vein 12 basally dilated; the lower margin of the discal cell basally dilated; vein 1b not dilated. Forewings with 1 tubular anal vein, or with 2 tubular anal veins (in L. megera, the upper weaker and terminating within the disc); the anal veins of the forewings representing 1b only, or comprising 1b and 1c; vein 1b simple. Forewings with a discal cell; vein 2 departing from the cell less than three-quarters of the distance from its base (from about halfway). Forewing veins 8 and 9 out of 7, 10 and 11 separate from the cell.

Hindwings 9 veined (L. megera), or 10 veined (L. maera); with a praecostal spur; with 2 anal veins (L. megera), or with 3 anal veins (conspicuously so in L. maera); exhibiting vein 1a; the anal veins comprising 1a and 1b, or comprising 1a, 1b and 1c. Hindwings with a closed discal cell; the transverse vein complete. 7 veins arising from the hindwing cell. The cell-derived hindwing veins 3+4 proximally joined.

Eggs, larvae, pupae. Eggs sub-globular to barrel-shaped; ostensibly more or less smooth (being only very finely ribbed and reticulated). The larvae shortly hairy; without bristly spines. On grasses.

Pupae smooth and rounded; conspicuously patterned to plain; without shining-metallic markings; exposed, with no coccoon; suspended from the tail (cremaster), with no median silk girdle.

British representation. 2 species. Lasiommata maera (Large-eyed Wall Brown), Lasiommata megera (Wall Brown). The adults abroad May to September.

Status in Britain. Indigenous (L. megera), or rare ocurrence representing occasional, genuine immigrants (vagrant/migrant mainland-European L. maera).

Distribution. Southern Scotland, northern England, English Midlands, East Anglia, Wales, southeast England, central southern England, southwest England, Isle of Wight, and Ireland. Frequenting open places. Habitats calcareous and non-calcareous.

Classification. Superfamily Papilionoidea. Satyridae.

Illustrations. • Lasiommata megera (Wall Brown): photos. • Lasiommata megera (Wall Brown): egg, larva, pupa. • Lasiommata (Pararge) megera (Wall Brown: Hübner/Curtis). • Lasiommata maera (Large-eyed Wall Brown): photos. • Larvae and pupae of L. maera and L. megaera: Duponchel (1849). • Lasiommata maera (Large-eyed Wall Brown: Kirby, 1907). • Lasiommata megera and Pararge aegeria: Kirb, 1907.

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2008 onwards. Insects of Britain and Ireland: butterflies. Version: 16th May 2016.’.