Insects of Britain and Ireland: butterflies

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L. Watson and M. J. Dallwitz

Boloria

Adults. Wingspan 41–50 mm; the fringes conspicuously light-and-dark banded. Slender-bodied to medium built; medium-bodied. The eyes glabrous. Antennae reaching noticeably less than halfway to the wingtips to reaching noticeably over halfway to the wingtip. The antennal clubs abrupt; flattened (blunt). Labial palps ascending. Having only 4 fully developed legs (forelegs with two tarsal joints and brushlike in males, those of females having 4 tarsal joints with short setae). 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 convexly curved; not scalloped (or only very slightly so). Uppersides of the forewings tawny, light brown, or orange-brown; contrastingly dark-veined; without a discal mark; with black venation, some short discal bars, and two posterior series, the inner of spots and the outer of crescents.

Hindwings. Hindwings broadly rounded; not tailed; with the outer margins scalloped (finely but definitely so). Uppersides of the hindwings tawny, light brown, or orange-brown; conspicuously dark-veined; conspicuously patterned; without a discal mark; coloured and patterned more or less like the forewings.

Undersides of wings. Undersides of the forewings colour-patterned as a pallid representation of the uppersides; not dark-veined (less conspicuously veined than the upper surfaces); without silvery-white subapical spots.

Undersides of the hindwings yellow, partly suffused ferrugineous except on the black-edged antemedian band, a subterminal series of small dark spots, and silvery-white blotches and spots; conspicuously dark-veined, or conspicuously dark-veined to not dark-veined (the venation sometimes less conspicuous than on the upper surface); with a subterminal row of spots between the discal spots and the terminal row; pearly-spotted or somewhat with silvery-metallic markings; with distinct silvery spots; with the spots of the subterminal row not silvery-centred; with only one discal silvery spot (B. euphrosyne), or with several discal silvery spots (B. selene).

Wing venation. Forewings 12 veined; without basally dilated veins. Forewings with 1 tubular anal vein; the anal veins of the forewings representing 1b only; 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, 9 and 10 out of 7.

Hindwings 9 veined; without a praecostal spur; with 2 anal veins; exhibiting vein 1a; the anal veins comprising 1a and 1b. Hindwings with a closed discal cell; the transverse vein complete. 7 veins arising from the hindwing cell. The cell-derived hindwing veins all arising independently of one another.

Eggs, larvae, pupae. Eggs broadly conical; longitudinally ribbed (about 20 ribbed). The larvae hairy; with rows of bristly spines; exposed feeders. On Viola, rarely on Primula.

Pupae ridged and angular; conspicuously patterned; with shining-metallic markings; exposed, with no coccoon; suspended from the tail (cremaster), with no median silk girdle.

British representation. 3 species. Boloria dia (Weaver's Fritillary), Boloria euphrosyne (Large Pearl-bordered Fritillary), Boloria selene (Small Pearl-bordered Fritillary). The adults abroad May to July, or August to September.

Status in Britain. Indigenous (B. euphrosyne and B. selene), or adventive, or formerly indigenous but now extinct (the British status of B. dia being uncertain, depending on 19th and early 20th Century records).

Distribution. Northern Scotland, 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.

Comments. Wing venation details from B. selene only.

Classification. Superfamily Papilionoidea. Nymphalidae.

Illustrations. • Boloria euphrosyne (Pearl-bordered Fritillary): photos. • Boloria euphrosyne (Pearl-bordered Fritillary): egg, larva, pupa. • Boloria selene (Small Pearl-bordered Fritillary: B. Ent. 386). • Boloria selene: B. Ent. 386, legend+text. • Boloria selene: B. Ent. 386, text cont.. • Boloria selene (Small Pearl-bordered Fritillary): egg, larva, pupa. • Larvae of B. dia, B. euphrosyne, B. selene: Duponchel (1849). • Boloria dia (Weaver’s Fritillary): From Hübner, 1805.. • Boloria dia (Weaver's Fritillary: Morris, 1893). • Boloria dia (Weaver's Fritillary), Melitaea didyma: Kirby, 1907. • Boloria euphrosyne (Pearl-bordered Fritillary), with Melitaea athalia (Heath Fritillary): Stephens (1828). • The smaller Fritillaries: Newman, 1871.


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

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