Synemon laeta is a moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 in the Castniidae

Castniidae

Castniidae, or castniid moths, is a small family of moths with less than 200 species: The majority are Neotropical with some in Australia and a few in south-east Asia. These are medium-sized to very large moths, usually with drab, cryptically-marked forewings and brightly coloured hindwings. They...

 family. It is found along the east coast of Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

.

Adults have a brown pattern on their forewings and scarlet hindwings with a brown marginal and submarginal arc. Males show territorial behaviour, chasing other intruding males away.

The larvae feed on Lomandra longifolia

Lomandra longifolia

Lomandra longifolia, commonly known as Spiny-head Mat-rush, Spiky-headed Mat-rush or Basket Grass is a perennial, rhizomatous herb found throughout eastern Australia. The leaves are 40 cm to 80 cm in long, and generally have a leaf of about 8mm to 12mm wide . It grows in a variety of soil...

. They feed inside the culm of the foodplant at ground level.