Black Boneens
The "Black Boneens" is the nickname of a fictional rival regiment mentioned in "The Mutiny of the Mavericks" by Rudyard Kipling.
The term Boneen is Newfoundland Gaelic dialect for a young pig (derived from Dineen > Irish Gaelic). The slang probably indicates that the unit is either from Newfoundland or the Maritimes region of Canada or served there during its history.
They seem to be a rowdy lot with poor discipline. As an example, the men of the "Mavericks" mention in barracks gossip that a platoon of the "Boneens" were currently being court-martialed for almost killing a new recruit while hazing him. It seems the recruit had been trying to spread Fenian propaganda and encourage desertion and insurrection in the unit. The former was tolerated but the latter, disloyalty to the Regiment, seemed to be the cause of the incident.
The Real "Boneens"
The regiment seems to resemble the 100th (Prince of Wales's Royal Canadian) Regiment of Foot, a Canadian regiment raised in 1858 to serve in India during the Mutiny. In 1881, it was paired with a former Honourable East India Company regiment to form The Prince of Wales's Leinster Regiment (Royal Canadians).