Type material for 335 nominal species of fossil hexapods are in the Invertebrate Paleontology Collections of Yale University's Peabody Museum of Natural History. Primary types for 236 nominal species include 227 holotypes, 6 neotypes and 6 syntypes (representing three nominal species). Secondary types for 52 nominal species include 4 allotypes and 90 paratypes. Tertiary types for 91 nominal species include 698 hypotypes. Most types are from Elmo (Kansas), Mazon Creek (Illinois), and Florissant (Colorado) and have been described by F.M. Carpenter, T.D.A. Cockerell, Anton Handlirsch and R.J. Tillyard.