Little is known of 2nd Lt. Souter at this time. The follwong report notes that he and his pilot were killed in April, 1917.

JAMES MITCHELL SOUTER March 28, 1894— April 11, 1917
Lieutenant, Royal Flying Corps.
Son of James E. Souter; b. Hamilton; ed. Hamilton p.s. and c.i.; Applied Science
1914-16; c.o.T.C; 13th Regt., Lieut.

In March 1916 he was appointed to the 133rd Battalion, and went overseas in October. He then transferred to the Royal Flying Corps, and went to France in March 1917, joining first the 12th and later the 59th Squadron. After less than a month's service he was killed in action near Arras. With six other machines he went out in the direction of Douai, and none of them returned. After the Germans retired from this
front he was found with his Pilot, beside the machine, and they were buried where they had fallen.

source (University of Toronto - Roll of Honour)