Fig. 9

Bullae in wings of fossil crowngroup and stemgroup mayflies. A, B Undescribed species of Hexagenitidae † (Ephemeroptera), forewing. Burmese amber, Mid-Cretaceous, ca. 99 ma. C, D Undescribed species of Baetidae: Palaeocloeoninae † (Ephemeroptera), forewing. Burmese amber, Mid-Cretaceous, ca. 99 Ma. E, F Undescribed species of Australiphemeridae † (Ephemeroptera), forewing, first record from Lebanese amber, Lower Cretaceous, ca. 129 Ma. G, H holotype of Protereisma insigne † (Ephemerida: Permoplectoptera: Protereismatidae), hind wing, Lower Permian of Kansas, ca. 272 Ma., courtesy of the Yale Peabody Museum, Division of Vertebrate Paleontology, Yale University, Peabody.yale.edu. Photographs by S. Butts, 2023