Leo Diamond

Born: 29 June 1915, New York City, New York, USA
Died: 15 September 1966, Los Angeles County, California, USA

Leo Diamond was a famous harmonica player and composer of the 1930s and 1940s who appeared in several movies, often as a member of the Harmonica Rascals or his own group The Solidaires. 

Coney Island (1943) as Solidaires Leader (Credited as Leo Diamond and His Solidaires)

Leo Diamond is in the red top at the front. The other members are Abe Diamond, Leo's brother, Richard Hayman, in the glasses, Pete Maggio and Harry Roller. The lady is unknown to me.