Orsotriaena medus

Orsotriaena medus (Fabricius, 1775)
Bush Brown
(previously known as Mycalesis medus)
SATYRINAE, NYMPHALIDAE, PAPILIONOIDEA

Don Herbison-Evans
(donherbisonevans@yahoo.com)
and
Stella Crossley

Orsotriaena medus
(Specimen: courtesy of the Macleay Museum, University of Sydney)

The eggs of this species are pale green and have a diameter of about 1 mm. They are laid on the underside of a leaf of a food plant. The Caterpillars of feed on various members of the Grass family ( POACEAE ), including :

Cogon Grass ( Imperata cylindrica ),

Rice ( Oryza sativa ), and

Guinea Grass ( Panicum maximum ).

The caterpilars are variously: white, pink, yellow or green. They have two pairs of horns on the head, one pair pointing forward, and one back. They grow to a length of about 4 cms.

They pupate hanging from a cremaster from a leaf of the food plant. The pupa is brown with a dark line along each side, and has a pointed head. The pupa has a length of about 2 cms.

underside
(Photo: courtesy of Riandika Abdul Hafizh Alhaqi, Java)

The wings of the adult butterflies are dark brown, with a faint pale stripe across each wing. The undersides are similar, except that each wing has at least two eyespots. The butterflies have a wingspan of about 4 cms.

The species is found as various subspecies across south-east Asia, including

and the subspecies moira Waterhouse & Lyell, 1914, is found in Australia in

Queensland.

Further reading :

Michael F. Braby,
Butterflies of Australia, CSIRO Publishing, Melbourne 2000, vol. 2, pp. 470-471.