Melliss was born in Mhow, British India, on 12 September 1862, the son of Lieutenant General George Julius Mellis of the Indian Staff Corps.

He served with the North Nigeria Regiment in West Africa 1898–1902, and in Ashanti during 1900, including at the relief of Kumassi in the War of the Golden Stool.

On 30 September 1900 at Obassa, Ashanti, Captain Melliss gathered together a party of men and charged into the bush at the head of them into the thick of the enemy.

[2] Meliss was promoted major on 10 July 1901,[3] and for the same action that won him the Victoria Cross he was also awarded the brevet rank of lieutenant colonel on the following day.

[4][5] He vacated his appointment as second in command of the Northern Nigeria Forces in late 1902, and reverted to the Indian Army, where he was posted to the 1st Bombay Grenadiers.

Major General Melliss was attached to the 6th (Poona) Division of the British Indian Army[10] as it moved into what was then the Ottoman province of Basra in 1914.

Transported upriver to Baghdad by steamship, Melliss remained in hospital and unable to travel as the survivors of the 6th Division were marched north toward Anatolia.