Ribbed Case Moth
(previously known as Thyridopteryx nigrescens)
|These Caterpillars live and pupate in a silken case. Initially the case has sparse bits of debris attached to it.|
early instar, magnified
(Photo: courtesy of Andy Doldissen, Sydney, New South Wales)
|Later it develops several longitudinal ribs, and becomes quite bare, unlike many other species in PSYCHIDAE which cover their case in pieces of vegetation.|
(Photo: courtesy of Bruce Anstee, Riverstone, New South Wales)
|The caterpillars normally only protrude the head and thorax, which have a hard orange and dark blue skin, from their case.|
The abdomen is greyish and soft, so they normally keep that inside the protective case.
The caterpillars have been found feeding on:
The case can grow to a length of up to 4 cms.
(Photo: courtesy of Merlin Crossley, Melbourne, Victoria)
When metamorphosis is complete, the male extrudes the pupa from the posterior end of the case in order to emerge.
The male is has a hairy black or brown head and body, with a fringe of pale hairs around the head and a tuft of yellow hairs on the tip of the abdomen. The forewings are transparent and the hindwings are variously blue, black or brown. The wingspan is about 2.5 cms.
The female is wingless, with a tiny head and thorax. She stays within her case for fertilisation, and lays her eggs within the case.
When the eggs hatch, the small caterpillars move to the outside of the case and onto the food plant. Though only about 3mm long, these small caterpillars each have a small conical case, which they hold perpendicular to the surface they are on.
The species is found in
Further reading :
Ian F.B. Common,
Moths of Australia,
Melbourne University Press, 1990, p. 180.
Descriptions of some new Australian lepidopterous insects,
in E.J. Eyre (ed.) :
Journals of Expeditions of Discovery into Central Australia and Overland from Adelaide to King George's Sound in the Years 1840-1; sent by the colonists of South Australia, with the sanction and support of the Government: including an account of the manners and customs of the Aborigines and the state of their relations with Europeans,
London : T. & W. Boone Vol. 1 (1845), p. 437, Plate 5, fig.1.
Peter B. McQuillan, Jan A. Forrest, David Keane, & Roger Grund,
Caterpillars, moths, and their plants of Southern Australia,
Butterfly Conservation South Australia Inc., Adelaide (2019), p. 41.
Tropical Queensland Wildlife from Dusk to Dawn Science and Art,
LeapFrogOz, Kuranda, 2015, p. 184.
Paul Zborowski and Ted Edwards,
A Guide to Australian Moths,
CSIRO Publishing, 2007, p. 48.
(updated 25 October 2010, 24 October 2014, 24 March 2018, 12 May 2019, 22 October 2020)