Insects of Britain and Ireland: butterflies

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L. Watson and M. J. Dallwitz



Adults. Wingspan 75–95 mm; the fringes conspicuously light-and-dark banded. Slender-bodied to medium built; very short-bodied. The eyes glabrous. Antennae reaching noticeably less than halfway to the wingtips. The antennal clubs somewhat gradual-elongate; curved; flattened (blunt, not pale-tipped). Labial palps ascending (appressed to frons). Having all 6 legs fully developed and operational for walking. Fore-legs with a tibial epiphysis. Tibiae of middle legs without spurs. Posterior tibiae 2-spurred.

Forewings. Forewings apically blunt. The outer and hind margins angled at about 100–105 degrees. The outer margins more or less straight to concavely curved. Uppersides of the forewings white to cream, or yellow, or primrose; not conspicuously dark-veined; without a discal mark; with conspicuous dark transverse bars.

Hindwings. Hindwings broadly rounded (the inner margin concave); conspicuously long- tailed; with the outer margins scalloped. Uppersides of the hindwings white to cream, or yellow, or primrose; conspicuously patterned. Uppersides of the hindwings conspicously eye-spotted. The eye-spots 1; near the tornus. Uppersides of the hindwings without a discal mark; with dark transverse streaks from the costa, black with blue crescentic spots along the outer margin, and a black, blue and orange eye-spot on the hind margin near the tail.

Undersides of wings. Undersides of the forewings complexly colour-patterned as a pallid duplication of the upperside.

Undersides of the hindwings complexly colour-patterned as a pallid duplication of the upperside; eye-spotted. The eye-spots 1; near the tornus. Undersides of the hindwings without a discal mark.

Wing venation. Forewings 13 veined; with basally dilated veins to without basally dilated veins (all the basal veins gradually widening basally). Forewings with 2 tubular anal veins; the anal veins of the forewings comprising 1b and 1c (the upper anal vein weaker, but conspicuous and reaching the termen); 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 out of 7 (stalked), 9 connate with 7 on the cell, 10–12 separate.

Hindwings 8 veined; with a praecostal spur; with 1 anal vein; lacking vein 1a; the anal veins representing 1b only. 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, or 4+5 proximally joined (at least, these almost connate on the cell).

Eggs, larvae, pupae. Eggs sub-globular (?); more or less smooth. The larvae with a pair of tentacles from segment 2 (these retractile); exposed feeders. On woody Rosaceae.

Pupae rather ridged and angular; exposed, with no coccoon; not suspended, but attached at the tail and secured by a median girdle of silk.

British representation. 1 species. Iphiclides podalirius (Scarce Swallow-tail). The adults abroad July to September.

Status in Britain. Rare ocurrence representing occasional, genuine immigrants (probably, additional to accidental introductions).

Distribution. Southeast England, central southern England, southwest England, and Isle of Wight. Frequenting open places. Habitats calcareous and non-calcareous.

Comments. Flight rapid and sustained, sometimes gliding.

Classification. Superfamily Papilionoidea. Papilionidae.

Illustrations. • Iphiclides podalirius (Scarce Swallow-tail): photos. • Iphiclides podalirius (Scarce Swallow-tail): B. Ent. 578. • Iphiclides podalirius (Scarce Swallow-tail): B. Ent. 578, legend+text. • Iphiclides podalirius (Scarce Swallow-tail): B. Ent. 578, text cont.. • Iphiclides podalirius (Scarce Swallow-tail: Hübner/Curtis). • Larva and pupa of I. podalirius: Duponchel (1849).

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.’.