Have you read this?
"1882-1883 Hugo Hemmann
Hugo Hemmann was born in Saxe-Weimar, in the present state of Thuringia in central Germany in March, 1859. Hugo Hemmann was brother of the violinist Friedhold Hemmann (August 15, 1845-after 1910) and the cellist Carl Hemmann (1851-before 1910). They emigrated together to the U.S. in 1866. Both Friedhold Hemmann and Carl Hemmann played with the New York Philharmonic Society in 1877-1879. Hugo Hemmann was the Principal oboe of the Boston Symphony during its second season 1882-1883. Carl Hemmann by the 1891-1892 season was playing cello, probably Principal, in the New York Symphony under Walter Damrosch. By 1889, Hugo Hemmann, Carl Hemmann and Friedhold Hemmann all were musicians in New York City. Carl Hemmann died after 1922. Friedhold Hemmann died after 1916."