Sceliphron caementarium, also known as the “Yellow-legged mud-dauber” is a solitary sphecid wasp famous for building nests out of mud and packing them with paralyzed spiders on which they lay a single egg and seal it all up. The developing larva will consume the paralyzed spiders and emerge after pupation. This female seemed to be searching for just the right sort of mud to build her nest.
2021-07-21