In the warmer southeastern U.S., they may appear more blue or purple in color.
Sweat bees have pollen baskets on their legs and collect it like other bees. They can also sting like other bees. Adults feed on flower nectar they collect, or steal it from aphids. They can be found on flowers or on tree bark. Larvae feed on both pollen and nectar.
Females nest in rotting wood, in tunnels bored out by other insects (like beetle larvae), or underground in loose soil. A female fills the end of the tunnel with cells and stuffs a pollen grain in each one with some nectar. Then, she will lay one egg on each grain. The larvae overwinter and emerge as adults in the spring having grown to maturity by feasting on the nectar and pollen grain left by the mother.