Adult mud daubers are 3/4 to 1 inch long wasps, varying in color by species from dull black to black with bright yellow markings to iridescent blue-black. The best identifying feature is the longer, narrow "waist".
These are solitary wasp species, with nests constructed and provisioned by individual mated females. Eggs of mud daubers are laid singly on hosts in cells in mud nests provisioned with food, sealed and abandoned. Larvae grow up to 1 inch long and are cream-colored, legless and maggot-like. They pupate in cocoons within the cells and overwinter in nests. There can be several generations annually.
Mud daubers are a solitary wasp species; although capable of stinging, they are rarely aggressive. Mud dauber nests can be a nuisance in garages, under eaves and in other buildings.
Mud dauber nests can simply be removed with a putty knife. Control adult wasps with a fly swatter or a wasp and hornet aerosol spray. After using insecticides, scrape away the nest and dispose of it to prevent emergence of developing young.