Insects of Britain and Ireland: butterflies
Adults. Wingspan 70–92 mm; the fringes conspicuously light-and-dark banded. Slender-bodied to medium built; very short-bodied. The eyes glabrous. Antennae reaching noticeably over halfway to the wingtip. The antennal clubs rather gradual-elongate (elongate); not curved; 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 95 degrees. The outer margins concavely curved and angulated; scalloped. Forewings with the outer margin both angulated and markedly scalloped. Uppersides of the forewings dark fuscous, or fuscous and purple (the disc spectacularly showing purple when viewed obliquely in the male); with rather conspicuous venation; inconspicuously eye-spotted (in the male, via a small, dark, light-centred spot in the middle towards the outer margin, representing transmission from the underside), or without eye-spots. The eye-spots when present, 1; mid-posterior. Uppersides of the forewings with an irregular interrupted central white fascia, and an interrupted white band towards the apex.
Hindwings. Hindwings broadly rounded to broadly angular (markedly more angular in the male); not tailed; with the outer margins scalloped. Uppersides of the hindwings dark fuscous, or purple and fuscous (the disc spectacularly showing purple when viewed obliquely in the male); with rather conspicuous venation; conspicuously patterned. Uppersides of the hindwings eye-spotted. The eye-spots 1; mid-posterior to near the tornus. Uppersides of the hindwings coloured like the forewings, with an oblique white median fascia falling short of the dorsum, and a black, orange-ringed and sometimes light-centred eye-spot towards the tornus.
Undersides of wings. Undersides of the forewings attractively and very complexly colour-patterned (see illustrations), with white markings corresponding with those on the uppersides and with a conspicuous orange-ringed and blue-centred eye-spot in the middle towards the outer margin; with very conspicuous venation; conspicuously eye-spotted. The eye-spots 1; mid-posterior.
Undersides of the hindwings ground-coloured brownish and suffused ferrugineous, with a white median fascia larger than that of the upperside, and with a large, round, mid-posterior orange blotch containing a small, black, blue-centred eye-spot; with very conspicuous venation; eye-spotted. The eye-spots 1; mid-posterior to near the tornus.
Wing venation. Forewings 12–13 veined; without basally dilated veins. Forewings with 2 tubular anal veins (the upper one weaker and falling well sjhort of the termen); the anal veins of the forewings comprising 1b and 1c; vein 1b simple. Forewings without a discal cell (the transverse vein absent between veins 4 and 5). Veins 8 and 9 out of 7, the others separate.
Hindwings 9 veined; with a praecostal spur; with 2 anal veins (the lower stronger than the upper); exhibiting vein 1a; the anal veins comprising 1a and 1b. Hindwings without a closed discal cell; the transverse vein incomplete (lacking between veins 4 and 5).
Eggs, larvae, pupae. Eggs barrel-shaped to broadly conical (tapered to the apically concave apex); longitudinally ribbed (about 12-ribbed). The larvae hairless (scabrous); slug-shaped, without tentacles on segment 2 (but with a pair of large, horn-like appendages on the head); without bristly spines; exposed feeders. On Salix caprea.
Pupae ridged and angular; fairly conspicuously patterned (whitish, tinged with green, with whitish oblique lines on the sides and following the wing venation); without shining-metallic markings; exposed, with no coccoon; suspended from the tail (cremaster), with no median silk girdle.
British representation. 1 species. Apatura iris (Purple Emperor). The adults abroad July.
Status in Britain. Indigenous.
Distribution. English Midlands, East Anglia, Wales, southeast England, central southern England, and southwest England. Frequenting woodland. Habitats calcareous and non-calcareous.
Comments. A strong flier, often frequenting tree tops and soaring, sometimes gliding.
Classification. Superfamily Papilionoidea. Nymphalidae.
Illustrations. • Apatura iris (Purple Emperor): photos. • Apatura iris (Purple Emperor: B. Ent. 338). • Apatura iris (legend+text: B. Ent. 338). • Apatura iris (text, cont.: B. Ent. 338). • Apatura iris (Purple Emperor): egg, larva, pupa. • Larva and pupa of A. iris: Duponchel (1849). • Apatura iris and Lodoga camilla: Newman, 1871.
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. delta-intkey.com’.