Problem: Umbrella wasps
Unlike the social yellow jackets, many species of wasps, including the potter and mason wasps, mud daubers, and spider wasps, live alone. Most of them build nests of mud and sand in which they raise their young. Many of these wasps feed on insects; a few feed on pollen and nectar. These wasps are not as aggressive and protective of their nests as are yellow jackets and do not sting as readily. If highly provoked, however, they can sting, causing swelling, itching, and more generalized symptoms in sensitive individuals.
Even though many solitary wasps are docile, they are often confused with yellow jackets, and it is best to avoid them. To remove them from the vicinity, you must eliminate the nests.