Potter wasp with its prey. Potter wasp (Eumenes flavopicta) with a caterpillar it has caught and paralysed. Potter, or mason, wasps build their pot-shaped nests from mud, then deposit the larva of a moth or beetle inside, which they have paralysed with their sting. On the inner side of the nest they lay an egg, which hatches into a larva that feeds on the still-living prey.