Mud Dauber

a common name for a wasp that construct its nest of mud. The black and yellow mud dauber is widely distributed solitary sphecid wasp that hunts spiders and builds characteristic mud nests for their offspring. In each cell of her nest, a female mud dauber lays a single egg which she provisions with up to 25 live, paralyzed spiders. 
I don't want to disturb this nest ... on the other hand I like the spiders, because they are killing the little ants, that come into the house, and nothing works better than those daddy longlegs. They suck the blood I think out of the ants, because I find dead little ants on the floor, where the spider is hanging above.