Ambulyx montana is a species of 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...

, Vietnam

Vietnam

Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

 and Burma.

It is similar to Ambulyx semiplacida

Ambulyx semiplacida

Ambulyx semiplacida is a species of moth of the Sphingidae family. It is known from Taiwan.It is similar to Ambulyx placida, but the forewing upperside subterminal line is more strongly arched and the yellow proximal border is broader....

but larger, with a more elongated forewing and paler grey. Furthermore, the forewing upperside subbasal spot posterior to the cell is smaller, the basal area of the hindwing upperside is shaded with grey at least to the medial line and along the inner margin of the tornus.