Pipe organ mud dauber

Insect nests spotted on the underside of the observation tower at Huntley Meadows Park. The nests are made of mud. These nests were built by a type of wasp known as Pipe organ mud daubers. Notice the small spider that is shown in the upper-right part of the nest in Photo 2. Pipe organ mud daubers "...stock their nests with spiders, which serve as food for their offspring." Source Credit: Wikipedia