Yellowjackets are bee-sized social wasps that build paper nests, usually underground. They usually have beelike black and yellow bands on their abdomens, but unlike honeybees, they are not hairy, nor do they collect pollen. Yellowjackets have yellow or white faces. When resting, they usually hold their wings down their back (not spread out). Right before landing, they often fly quickly side to side.
Yellowjacket nests are made of paper like those of paper wasps, but they have multiple parallel layers of comb with downward-facing cells (paper wasps always only have a single layer of cells). Yellowjacket nests are always enclosed in a wood-pulp paper envelope built by the wasps.
Yellowjackets are widely, and incorrectly, called "sweat bees" in Missouri.
Yellowjackets are a significant stinging threat: They nest in colonies and aggressively defend their nest as a group. Individuals can sting repeatedly.