Dolichovespula maculata is a eusocial wasp of the cosmopolitan family Vespidae. Its colloquial names include the bald-faced hornet, bald hornet, white-faced hornet, white-tailed hornet, spruce wasp, blackjacket, and bull wasp. This species is a yellowjacket wasp, not a true hornet (genus Vespa). Colonies contain 400 to 700 workers, the largest recorded colony size in its genus, Dolichovespula. It builds a characteristic large hanging paper nest up to 58 centimetres (23 in) in length. Workers aggressively defend their nest by repeatedly stinging invaders.
Baldfaced hornets are distinguished from other yellowjackets by their white and black coloring. It has a white or “baldfaced” head, which is the source of its colloquial name. These wasps also have three white stripes at the end of their bodies. They are notably larger than other species of Dolichovespula, as adults average about 19 millimetres (0.75 in) in length. Queen and worker wasps have similar morphologies. However, workers are covered by small hairs while the queen remains hairless. Queens are always larger than workers in their colonies, though size distributions can vary in different nests and workers in one colony might be as large as a queen in a different one.