Yellowjackets

Most are in the genus Vespula
Family: 
Vespidae (a wasp family) in the order Hymenoptera (ants, bees, wasps)
Description: 

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.

Size: 
Length: about 1/2 inch (worker).
Habitat and conservation: 
Missouri's two statewide native species most often nest underground, having started the nest in a cavity such as a rodent burrow. Though there may be a large paper nest beneath the soil, all you might see is a hole with wasps flying in and out of it. Yellowjackets can also nest in trees, attics and sheds. The non-native German yellowjacket prefers to build its nests in buildings, not underground, and as it spreads, more people will encounter that species.
Foods: 
All three species feed on a large variety of insects, including many that are injurious to crops, gardens and landscaping. Larvae, in the nest, are fed such insects, which the adults collect and chew up for them. Yellowjackets also eat flower nectar, juices from fruits and other sweets. Because they commonly feed from food scraps, soda cans and garbage, foraging workers often get close to people and therefore pose potential stinging hazards.
Distribution in Missouri: 
Two native species occur statewide, the eastern yellowjacket (V. maculifrons) and southern yellowjacket (V. squamosa); the introduced German yellowjacket (V. germanica) is expanding its range and will eventually occur statewide, especially in urban areas.
Status: 
Common. People rightly fear yellow jackets and other social wasps that are capable of stinging en masse. But as with many animals capable of powerfully affecting humans, these wasps have earned a place of respect in our culture. Note, for instance, the many sports teams that are named "yellowjackets," "hornets" and so forth.
Life cycle: 
Queens overwinter alone in a protected site such as under bark or in a wood pile. In spring the queen begins her nest and starts laying eggs, which hatch as female workers. The workers soon take over the colony’s tasks, allowing the queen to just lay eggs. The colony grows; by September it can contain 5,000 workers. Then the queen lays eggs for males and new queens. Once grown, these leave the nest and mate; the workers, original queen and males die; and the newly fertilized queens hibernate.
Human connections: 
Although these wasps do much that benefits humans, their capacity for colonial, defensive stinging makes them a major pest when they nest near people, especially since some people are allergic to bee and wasp venom. If you want to eliminate a yellowjacket nest, consult a licensed exterminator.
Ecosystem connections: 
Yellowjackets are predators and pollinators, but they are also connected with species that have evolved to have colors that "mimic" the black-and-yellow pattern of these stinging insects. Various species of flies and moths—completely incapable of stinging—are avoided because of the resemblance.
Shortened URL
http://mdc.mo.gov/node/6672