AbstractsBiology & Animal Science

The genus Ochodaeus Serville contains approximately sixty species and is World wide in its distribution. One-half of these species are known from the Nearctic and Neotropic regions. Adults of six previously described species common to the United States have been studied in detail. The mandibles, stridulatory peg, and male genitalia of these species have been described and figured. During the course of this study, one of these taxa was found to be a complex of closely related species. The Ochodeaus pectoralis species complex is erected here to contain the nominate species O. pectoralis Le Conte, and two new species, O. howdeni n. sp. and O. ritcheri n. sp., which are described in this work. The other five species considered are O. biarmatus Le Conte, O. inarmatus Schaeffer, O. kansanus Fall, O. praesidii Bates, and O. simplex Le Conte. The mandibles, stridulatory peg, and male genitalia have provided very useful characters in the delineation of species. The most useful part of the male genitalia was the aedeagal sac. A tabular key to the species considered in this study, and a dichotomous key to the species of the O. pectoralis species complex are presented.