Hey everybody, long time no see. I'm pretty sure everyone was doing studies on Bee Hybirdization back then, but I'll stick with the orthodox history.
The Africanized honey bee in the western hemisphere descended from 26 Tanzanian queen bees (A. m. scutellata) accidentally released by a replacement bee-keeper in 1957 near Uberlândia, Minas Gerais State in the southeast of Brazil from hives operated by biologist Warwick E. Kerr, who had interbred honey bees from Europe and southern Africa. Hives containing these particular queens were noted to be especially defensive. Kerr was attempting to breed a strain of bees that would produce more honey and be better adapted to tropical conditions (i.e., more productive) than the European bees used in South America and southern North America. The hives from which the bees were released had special excluder grates, which were in place to prevent the larger queen bees and drones from getting out and mating with local (non-African) queens and drones. Unfortunately, following the accidental release, the African queens and drones mated with local queens and drones, and their descendants have since spread throughout the Americas.
A pleasent surprise that my ID still works!