I just received the photo above and a note from a fellow named William Orr, principal of Hillsborough High School in Florida, whose father served on Ascension Island with the 38th Engineers at about the same time as my father.
Orr's father was in a band some of the men formed on the island, called The Wideawakes, named after the airfield they built, Wideawake Field--still in operation today. This is the first I've heard of the band, though it makes sense, on a desert island, that men would organize something like that to while away the time.