Contrary to popular belief the Irish invented organized crime in America. Alot of underworld slang comes from Irish influence. They contributed to the first gangs. And alot of staples of the subculture. They're are the single most influential group besides the Italians that made the criminal underbelly what it is today.

Street Gangs to me implies modernity. Signs, graffiti, identifiable clothing. While they were responsible for the first gangs, they were less like modern street gangs and more like mob crews in my opinion. Independent chieftains. And the Italian had street gangs too. Still do. 10th and Oregon for example. It wasn't until they were consolidated into the mafia by the Sicilians that it began to take shape. But even then the early mafia was more like street gangs. It wasn't until Prohibition that they all evolved into what is now considered a mobster.

And that was the problem with the Irish. They had a desire and a talent for organized crime, but no structure. It's why the Mafia has outlasted them and most ethnic criminal waves for that extent