From the Super Mario Wiki
Buzzbees are insect-like enemies only appearing in Donkey Kong 3. They are one of the most fast and aggressive enemies in the game, only appearing after the twelfth round (ninth in the NES version) when Donkey Kong knocks them out of their hive. It is Stanley's job to protect his greenhouse by shooting the bugs with insecticide, while at the same time keeping Donkey Kong at bay. Other enemies related to Buzzbees include Beespys, Buttiflys, Beetles, Moths, Creepys, Beebombs, Vine Eaters, and Queen Buzzbees, which Buzzbees will occasionally try to protect. Excluding ports and remakes, Buzzbees have not appeared in a new game since Donkey Kong 3.