Mesojassoides is a genus of extinct leaf hopper from the Late Cretaceous, approximately 70 - 66 million years ago, Fox Hills Formation.^[1] The genus contains a single species Mesojassoides gigantea, described from a fore wing found in 1932 by C.H. Dane and W. G. Pierce in Adams County, Colorado.^[1] Described by Paul W. Oman in 1937, the genus was named for the similarity in vein structure between the holotype and the modern genus Jassus.^[1] The holotype specimen, National Museum of Natural History #75521, is 12 millimetres (0.47 in) long and nearly complete, missing the clavus and a small section of the costal margin.^[1] The specimen indicates M. gigantea was similar in size to the largest modern leaf hopper species.^[1]