No sign of John Dunmore Lang Bruce in deaths between 1930-1940 in NZ (or anything remotely close)
Amelia Jane Bruce (possible marriage in the NZ bdm (if it is the correct lady) 1871 to George Adams she would be aged 32.
I notice in the IGI he is "John Dimmore Lang Bruce" born 1846 to Charles Bruce and
Jane Davis in Sydney, New South Wales, Australia