Cabinet photograph by the Smith studio of siblings Emma C. Mayo and Carroll Mayo. I believe they were from Naples, Maine. Not only was there a sibling pair of Emma C. Mayo and Carroll Mayo at Naples, but there were several photographers by the name of Smith in the area.
From brief online research, hopefully correct - corrections and additions requested:
Emma C. Mayo was born July 16, 1893 at Naples, Maine, the daughter of Ralph Mayo and Mary A. (Chaplin) Mayo. Emma had a younger brother, Carroll Wendell Mayo, born October 6, 1899, according to his record in the World War I Draft Registration Index, 1917-1919.
I believe it was this Emma C. Mayo who married Almon Rodney Welch at Naples, Maine, in 1934. She died in 1980 at Naples, Maine.
I don't know if Carroll ever married.
If you have corrections and/or additions to the information above, or if you feel that Emma Mayo and Carroll Mayo were another set of siblings, please leave a comment or contact me directly.