Izatha caustopa 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...

 of the Oecophoridae

Oecophoridae

Oecophoridae is a family of small moths in the superfamily Gelechioidea. The phylogeny and systematics of gelechoid moths are still not fully resolved, and the circumscription of the Oecophoridae is strongly affected by this....

 family. It is endemic to New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, where it is known very locally from the southern half of the North Island.

The wingspan

Wingspan

The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...

 is 24–26 mm for males and 29–31.5 mm for females. Adults have been recorded in January, February, December and April.

Larvae have been reared from dead branches of Fuchsia excorticata

Fuchsia excorticata

Fuchsia excorticata, the New Zealand Fuchsia also known as Kotukutuku, is a New Zealand native tree belonging to the family Onagraceae. It is found commonly throughout New Zealand and as far south as the Auckland Islands. It grows from sea level up to about 1,000 m, particularly alongside creeks...

. They feed during the winter months, driving burrows through the soft wood in all directions. They are full grown about October.