Metura elongatus

Metura elongatus (Saunders, 1847)
Saunders' Casemoth
(one synonym : Oiketicus saundersii Westwood, 1854)
OIKETICINAE, PSYCHIDAE, TINEOIDEA

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

Metura elongatus
case of early instar
(Photo: Don Herbison-Evans, Sydney, New South Wales)

These Caterpillars live and pupate in a silken shelter, which they initially cover with bits of leaf. As they grow larger, they attach parallel short twigs sparsely over the surface.

(Photo: courtesy of Evan Harris, Ipswich, Queensland)

(Photo: courtesy of Rebekah, Bathurst, New South Wales) They have been found feeding on a wide variety of plants, including :

Hanging Flax Lily (Dianella brevipedunculata, ASPHODELACEAE),
Flaxleaf Fleabane (Conyza bonariensis ASTERACEAE),
Cypress (Cupressus, CUPRESSACEAE),
Australian Heath (Epacris, ERICACEAE),
Silver Wattle (Acacia dealbata, MIMOSACEAE),
Gum Trees (Eucalyptus, MYRTACEAE),
Pine (Pinus, PINACEAE), and
Cotoneaster (Cotoneaster, ROSACEAE).
They are very adept at repairing their case with silk if it is damaged, and when threatened, seal the front opening until the danger is past, when they cut it open again.
The caterpillar is also adept at climbing, even on glass surfaces. It does so by attaching a series of bars of silk to the surface it wishes to climb, and using them like rungs on a ladder.

(Photo: courtesy of Ian McMillan, Imbil, Queensland)

Only the head and thorax have a chitinous armour. This is brightly coloured in black and orange. The animal keeps its unprotected off-white abdomen inside the case at all times.

case cut open to reveal the shy Caterpillar inside
(Photo: Don Herbison-Evans, Sydney, New South Wales)

The case can grow to a length of 12 cms or more. The caterpillar pupates within its silken case, which it usually hangs up on a wall, fence, or tree. The pupation period can be a few weeks to a few months, depending on the season and the weather.

pupa in the case
(Photo: Don Herbison-Evans, Sydney, New South Wales)

The female adult has no wings and cannot fly, so she remains in her case after emergence from the pupa. She is white with a brown head, and has a length of about 3 cms. When fertilised, through the anal end of the case, she lays several thousand eggs inside the case. In due course, the early instar caterpillars emerge from the case and go walk-about in the big wide world.

female adult
(Photo: courtesy of Ian Sims)

(Photo: courtesy of John Brickhill, Dickson, Australian Capital Territory)
The male, together with half of the pupal skin, emerges from the anal end of the case. He has wings and flies off. He is strikingly marked, with black wings, an orange hairy head, and a black and orange banded abdomen. The wings are short, and the abdomen is long and prehensile, presumably to facilitate reaching into the silken case of a female for copulation. He has a wingspan of about 3 cms, and a similar body length.

male adult moth
(Photo: courtesy of Chris Triggs, Campbelltown, New South Wales)

The species occurs in the eastern half of Australia, including

Northern Territory,

Queensland,

New South Wales,

Australian Capital Territory, and

Victoria.

male adult moth
(Photo: courtesy of Ian Sims)

The life history was illustrated by Arthur Bartholomew in 1867.