''Metallarcha zygosema'' is a

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

in the family

Crambidae Crambidae comprises the grass moth family of lepidopterans. They are variable in appearance, with the nominal subfamily Crambinae (grass moths) taking up closely folded postures on grass stems where they are inconspicuous, while other subfamilies ...

. It was described by

Oswald Bertram Lower Oswald Bertram Lower (28 February 1864 in Norwood, South Australia – 18 March 1925 in Wayville, South Australia)McQuillan, Peter B., Edwards, Ted & Camilleri, Jenny (26 September 2023) Oswald Bertram Lower (1864–1925): a South Australian pio ...

in 1897. It is found in

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, where it has been recorded from

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

and

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

. The

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

is about 20 mm. The forewings are light brown, with pale yellow markings outlined with darker brown. There is a large irregular cuneiform (wedge-shaped) patch from the base below the costa, its lower edge emitting a long slender streak along the inner margin to the anal angle. There is also a large irregular lunate mark in the middle of the wing, connected with the basal patch anteriorly by a short bar. The hindmarginal line is narrow and yellowish. The hindwings are pale fuscous, with a pale yellow basal patch."Descriptions of new species of Australian Lepidoptera, with notes on synonymy"

References

Moths described in 1897 Spilomelinae {{Spilomelinae-stub