Rapala varuna (Horsfield, 1829)
Indigo Flash
(previously known as Thecla varuna)
Don Herbison-Evans,
Stella Crossley

Rapala varuna
(Photo: courtesy of Bob Miller and Ian Hill)

These Caterpillars are a knobby yellow or green, with a dark dorsal line, and pink or white lines on each side. It has four knobs on each segment, each with an orange tip bearing stiff hairs.

Rapala varuna
(Photo: courtesy of Bob Miller and Ian Hill)

The caterpillars grow to a length of about 2 cms. They feed on the flowers and shoots of various species of plants, including :

  • Pongam ( Millettia pinnata, FABACEAE ),
  • Siris ( Albizia lebbeck, MIMOSACEAE ),
  • Millaa Millaa ( Elaeagnus triflora, PROTEACEAE ),
  • Red Ash ( Alphitonia excelsa, RHAMNACEAE ),
  • Loquat ( Eriobotrya japonica, ROSACEAE ), and
  • Lychee ( Litchi chinensis, SAPINDACEAE ).

    The caterpillars have also been suspected of being cannibalistic, attacking each other and attacking the pupae of other indivuals.

    Rapala varuna
          Rapala varuna
    (Photos: courtesy of Bob Miller and Ian Hill)

    The pupa is brown with darker markings, and is covered in short hairs. Its length is just over 1 cm. It is formed in debris at the foot of a foodplant.

    Rapala varuna
    (Photo: courtesy of Bob Miller and Ian Hill)

    The adult male butterflies are dark purple on top.

    Rapala varuna
    (Photo: courtesy of Todd Burrows, Tweed heads, New South Wales)

    The females are mauve, darkening towards the margin.

    Rapala varuna
    (Photo: courtesy of Chris Barnes, Bundaberg, Queensland)

    Underneath, both sexes are pale brown, and the wings each have a diagonal darker brown line, often outlined in white. Both sexes of the adult butterfliy have two tails near the tornus of each hind wing: one tail is thin and the other is knobbly. The undersides have a black spot beside each tail. The butterflies have a wing span of about 3 cms.

    Rapala varuna
    male underside
    (Photo: courtesy of Bob Miller and Ian Hill)

    The eggs are pale blue-green and round, with a diameter of about 0.5 cm. They are laid singly on flower buds or young shoots of a foodplant. It is possible that this habit, and the observed cannabalism, keeps the caterpillars to just one individual per plant, which together with the wide variety of plants on which the caterpillars feed, make it harder for parasitic wasps and flies to search for them.

    Rapala varuna
    female underside
    (Photo: courtesy of Bob Miller and Ian Hill)

    The species occurs as several races across south-east Asia, including

  • India,
  • Java,
  • Taiwan,
  • Vietnam,

    and as simsoni (Miskin, 1874) in Australia along the coast of

  • Queensland, and
  • New South Wales.

    Further reading :

    Michael F. Braby,
    Butterflies of Australia,
    CSIRO Publishing, Melbourne 2000, vol. 2, pp. 738-738.

    Thomas Horsfield,
    Descriptive Catalogue of the Lepidopterous Insects contained in the Museum of the Horourable East-India Company,
    Volume 2 (1829), pp. 91-92, No. 24.

    Frank Jordan & Helen Schwencke,
    Create More Butterflies : a guide to 48 butterflies and their host-plants
    Earthling Enterprises, Brisbane, 2005, pp. 23, 59.

    Helen Schwencke,
    Indigo Flash Rapala varuna: what is it with their caterpillars,
    Butterflies and Other Invertebrates Club,
    Metamorphosis Australia,
    Issue 79 (December 2015), pp. 31-32.

    Australian Butterflies
    Australian Moths

    (updated 7 May 2012, 23 November 2013, 10 August 2020, 8 September 2022)