Structure and Relationships of the Upper Carboniferous Insect, Eucaenus ovolis (Protorthoptera: Eucaenidae)

In 1885 S. H. Scudder described as Eucaenus ovalis a Penn- sylvanian (Upper Carboniferous) insect preserved in a concretion from the Francis Creek Shale in northeastern Illinois.Sub- sequently, a few additional specimens of the same insect were described by Melander (1903) and Handlirsch (1906aHandlirsch ( , 1911) ) from the same beds.Unfortunately, none of these specimens were sufficiently well preserved to give a satisfactory concept of the insect.In recent years, however, and for the most part through the activities of local amateur collectors, a surpiisingly large number of specimens of ovalis , many of them well pre- served, have been found in spoil heaps of strip mines dug to coal just beneath the shale (see Richardson and Johnson, 1971).As a result, Eucaenus ovalis is now one of the two or three best known Upper Carboniferous insects from anywhere in the world.The present account is based on a study of all the specimens of the species at present available.3 For the opportunity of examining new material, previously unstudied, we are grateful to the following individuals, who have collected the specimens and loaned them to us: Mr.