Ukulele and Calabashes Honolulu star-bulletin, July 23, 1912, Page 9 http://chroniclingamerica.loc.gov/lccn/sn82014682/1912-07-23/ed-2/seq-9/

The first group of Portuguese immigrants to Hawaii invented the ukulele after they arrived in August 1879 via the SS Ravenscrag. That ship included cabinet makers from Madeira Island, who brought the Medeiran machete. In their new country, ukulele inventors Manuel Nunes, José do Espírito Santo, and Augusto Dias developed the ukulele, and the Hawaiians adopted it (ukulele means "jumping flea" in Hawaiian).

George E. K. Awai and his Royal Hawaiian Quartet popularized the small, guitar-like instrument when they performed at the Panama Pacific International Exposition at San Francisco in 1915. From then on to the early 1920s, the ukulele became popular on the mainland United States.

From the University of Hawaii at Manoa Library: https://www.flickr.com/photos/uhmlibrary/