Theretra lifuensis 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 Sphingidae

Sphingidae

Sphingidae is a family of moths , commonly known as hawk moths, sphinx moths and hornworms, that includes about 1,200 species . It is best represented in the tropics but there are species in every region . They are moderate to large in size and are distinguished among moths for their rapid,...

 family. It is known from the Loyalty Islands

Loyalty Islands

The Loyalty Islands are an archipelago in the Pacific. They are part of the French territory of New Caledonia, whose mainland is away. They form the Loyalty Islands Province , one of the three provinces of New Caledonia...

.

The length of the forewings is 33.8-37.3 mm for males and about 40.1 mm for females. It is similar to Theretra clotho celata

Theretra clotho

Theretra clotho is a moth of the Sphingidae family. It is found from Sri Lanka, India , Nepal and Myanmar, east through China to Taiwan, South Korea and Japan, and then south-east through South East Asia as far as the Lesser Sunda Islands and Timor in Indonesia...

but distinguishable by the pink tone of the median band of the hindwing upperside. The forewing is less elongated and the outer margin is more convex. The forewing upperside is also similar to Theretra clotho celata but the ground colour is darker and more grey, the discal spot is clearly evident and there is a scalloped olive-green band present distal to the fourth postmedian line. The hindwing upperside has a pale median band distinctly tinged pink, especially in females.