Insects of Britain and Ireland: butterflies

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L. Watson and M. J. Dallwitz



Adults. Wingspan 25–30 mm; the fringes not banded. Medium built; short-bodied to medium-bodied. The eyes white-rimmed; notched or emarginate at the bases of the antennae and contiguous with the bases of the antennal sockets; hairy, or glabrous (?). Antennae reaching noticeably less than halfway to the wingtips to reaching about halfway to the wingtips. The antennal clubs gradual-elongate to abrupt (elongate?). Labial palps ascending. Having all 6 legs fully developed and operational for walking. Fore-legs without a tibial epiphysis. Tibiae of middle legs 2-spurred. Posterior tibiae 2-spurred.

Forewings. Forewings apically blunt to pointed. The outer margins convexly curved to more or less straight. Uppersides of the forewings violet- blue (males), or purple, or fuscous (females); without a discal mark; in the males, deep violet with a narrow black border; in females, dusky brown with violet on the disc.

Hindwings. Hindwings broadly rounded, or trapezoidal (more rounded than in Lampides boeticus); tailed; the tail filamentous and delicate (from vein 2). Uppersides of the hindwings violet- blue (males), or purple, or fuscous (females); conspicuously patterned, or plain; without a discal mark; in the males, deep violet with a narrow black border; in females, dusky brown with violet on the disc.

Undersides of wings. Undersides of the wings transversely patterned with numerous pale, sinuous lines.

Undersides of the forewings grey-brown, with numerous flexuose pale lines. Undersides of the forewings completely traversed ante-medianly by transverse lines (i.e., by contrast with Lampides boeticus, where they do not extend beyond the discal cell).

Undersides of the hindwings grey-brown with numerous flexuose pale lines, and at the anal angle near the tail two small, orange-bordered spots containing metallic green; with 1–2 black dots within small orange spots near the tornus; eye-spotted. The eye-spots 2; near the tornus. Undersides of the hindwings without a discal mark; with silvery-metallic markings.

Wing venation. Forewings 11 veined (?). Forewings with 1 tubular anal vein; the anal veins of the forewings representing 1b only; vein 1b furcate proximally to simple. Forewings with a discal cell. Forewing veins 7 missing, 8 and 9 stalked, 6 out of 9.

Hindwings 9 veined; without a praecostal spur; with 2 anal veins; exhibiting vein 1a; the anal veins comprising 1a and 1b. 7 veins arising from the hindwing cell. The cell-derived hindwing veins 3+4 proximally joined (connate only).

Eggs, larvae, pupae. The larvae woodlouse-shaped; associated with ants in the later instars. On Lotus, Melilotus, etc.

Pupae smooth and rounded.

British representation. 1 species. Leptotes pirithous (Bloxworth Blue, Lang’s Short-tailed Blue). The adults abroad August.

Status in Britain. Rare ocurrence representing occasional, genuine immigrants (from mainland-Europe).

Distribution. Central southern England.

Classification. Superfamily Papilionoidea. Lycaenidae.

Illustrations. • Leptotes pirithous (Lang’s Short-tailed Blue). • Leptotes pirithous (Lang’s Short-tailed Blue): From Hübner, 1805). • Plebicula dorylas, Leptotes pirithous: Kirby, 1907.

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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.’.