|Photo by Ned Harris 4/30/2014|
Paper wasps tending a nest on one of the restrooms in Sabino Canyon. Bug Eric (Eric Eaton) had this to say about them:
Yes, those are eggs in some of the cells. The capped ones have pupae inside. All wasps are the same species: Polistes major, but different subspecies. Yellow one is P. major major, dark ones are P. major castaneicolor. This might be a rather unusual situation.
More info on the wasps of this area can be found here (on the Arizona Sonora Desert Museum site).