The bumblebees, a group of bees with more than 250 species worldwide, are one of the three groups of bees which show a well-developed social behavior. They are present in most of the bio geographical regions of the world, but the Ethiopian, Australian, and Oceanic. The group is especially diverse in the Paleartic and Oriental regions, and is well represented in the new world, especially in the Western Neartic and Western Neotropical regions. The group was recently organized in 15 subgenera, three of them with species in the neotropics.