Eurypteryx geoffreyi 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 Thailand

Thailand

Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

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The length of the forewings is 31 mm for males and 38 mm for females. It is similar to Eurypteryx shelfordi

Eurypteryx shelfordi

Eurypteryx shelfordi is a moth of the Sphingidae family. It is known from Borneo and Sumatra.The length of the forewings is 42-46 mm. The abdominal anal tuft is dark brown, like the rest of the body. The antennae are cream dorsally and brown towards the base. The upperside of the thorax and abdomen...

but smaller. The abdominal anal tuft is black. The forewing upperside of the males has no discal spot and the forewing underside has no white preapical costal patch. The discal spot is yellowish. The hindwing underside is brown with a small yellowish discal spot. The marginal area is bounded by an indistinct submarginal line. The female differs from the male in the presence of a conspicuous discal spot on the forewing upperside formed from two partially fused white patches.