Prehistoric nests of Mud Dauber Wasps (Hymenoptera: Sphecidae) discovered in Transylvania, Romania. - Popa, Alexandra Florina; Kavruk, Valerii; Beldiman, Corneliu (Works of the National Museum of Natural History 'Grigore Antipa' / Travaux du Muséum National d'Histoire Naturelle 'Grigore Antipa', 2022)