What kind of black insect with a stinger flies and is smaller than a quarter inch Acts like a bee and kind of looks like an ant with wings in southeast Wisconsin?

I don't know but I know exactly what you are talking about! These little boogers can sting over and over. They're really tough to kill (ex. in trying to "smash" or "crush" it, seems to be impossible!). Does anyone know what this insect is?!?