A revision of the American species of Prionus Geoffroy, 1762 is presented. Prionus (Neopolyarthron) Semenov, 1899 and Prionus (Antennalia) Casey, 1912 are synonymized with Prionus Geoffroy, 1762. Homaesthesis LeConte, 1873 is considered a true subgenus of Prionus. Prionus (Homaesthesis) rhodocerus Linsley, 1957 and Prionus (Homaesthesis) linsleyi Hovore, 1981 are synonymized with Prionus simplex (Casey, 1912). Prionus beauvoisi Lameere, 1915 and Prionus (Neopolyarthron) debilis Casey, 1924 are synonymized with P. imbricornis (Linnaeus, 1767). Prionus (Neopolyarthron) townsendi Casey, 1912 and Prionus (Neopolyarthron) curticollis Casey, 1912 are synonymized with Prionus mexicanus Bates, 1884. Prionus batesi Lameere, 1920 is synonymized with Prionus aztecus Casey, 1912. Prionus hintoni Linsley, 1935 is synonymized with Prionus flohri Bates, 1884. Prionus (Antennalia) fissicornis parviceps Casey, 1912 is excluded as the synonym of Prionus fissicornis Haldeman, 1846 and instead synonymized with P. imbricornis (Linnaeus, 1767). Prionus (Prionus) validiceps Casey, 1912 is excluded from the synonymy of P. pocularis Dalman, 1817, and synonymized with P. (P.) californicus Motschulsky, 1845. Prionus (Prionus) tumidus Casey, 1912 is excluded from the synonymy of P. heroicus Semenov, 1907, and synonymized with P. (P.) californicus. The lectotype female and the paralectotype male of Prionus (Prionus) tristis are excluded from the synonym of P. (P.) heroicus and transferred to the synonym of P. (P.) californicus; the paralectotype female of P. (P.) tristis is maintained in the synonymy of P. (P.) heroicus. Prionus (Prionus) fontinalis Casey, 1914 is excluded from the synonymy of P. (P.) heroicus and synonymized with P. (P.) californicus. Prionus simplex is formally excluded from the Cerambycidae fauna of Oklahoma, USA. Comments on the page, plate, and figure of publication of Cerambyx laticollis Drury, 1773 are presented. Prionus (Trichoprionus) Fragoso & Monné, 1982 is considered a genus different from Prionus. Hypoprionus is designated as a replacement name for Prionellus Casey, 1924 and Cerambyx laticollis Drury, 1773 is designated as the type species. Comments on the type localities of Prionus emarginatus, Prionus palparis Say, 1824, and Prionus (Neopolyarthron) aztecus Casey, 1912 are presented. Prionus (Homaesthesis) integer sensu Linsley (1962) and Chemsak (1996) is described as P. (H.) geminus, new species. Comments on the date of publication of Prionus fissicornis Haldeman, 1846 are presented. Comments on the status of the syntypes of Cerambyx imbricornis Linnaeus, 1767 are also presented. Lectotype specimens for Prionus flohri Bates, 1884, Prionus (Prionus) tristis, and Prionus lecontei Lameere, 1912 are designated. Comments on the number of specimens used in the original description of Prionus californicus are presented, and a lectotype for this species is designated. New state records are presented for Prionus emarginatus Say, 1824; P. imbricornis (Linnaeus, 1767); P. aztecus Casey, 1912; P. poultoni Lameere, 1912;...

Family-group names proposed for beetles belonging to the family Cerambycidae are catalogued and their availability is determined using the rules of the current International Code of Zoological Nomenclature. A synoptic classification of the family summarizes the validity of the names. Type genera of all family-group names are listed and the type species and stems of genera of available family-group names are included. A new family-group name, Elytracanthinini Bousquet (type genus: Elytracanthina Monn, 2005, a replacement name for Elytracantha Lane, 1955) is proposed for Elytracanthinae Lane, 1955. Ichthyosoma armatum Montrouzier, 1855 is designated as type species of Icthyosoma Boisduval, 1835. Reversal of precedence is used to preserve the validity of the following family-group names: Anaglyptides Lacordaire, 1868 (over Anaglyptisidae Gistel, 1848 [Buprestidae]); Dryobiini Arnett, 1962 (over Dryobiadae Gistel, 1856 [Ptinidae]); Hemilophitae Thomson, 1868 (over Amphionychitae Thomson, 1860) and Hétéropsides Lacordaire, 1869 (over Dichophyiaeidae Gistel, 1848). The following family-group names, although junior synonyms, are preserved as valid until an application is submitted to the International Commission on Zoological Nomenclature; in these cases a reversal of precedence could not be applied: Eurypodini Gahan, 1906 (over Zaracinae Pascoe, 1869); Macronides Lacordaire, 1868 (over Enchapteritae Thomson, 1861); Pyresthides Lacordaire, 1868 (over Pseudolepturitae Thomson, 1861 and Erythrinae Pascoe, 1866) and Stenoderinae Pascoe, 1867 (over Syllitae Thomson, 1864). A total of 238 valid cerambycid family-group names (413 available names) are recognized in the following 13 subfamilies: Vesperinae (1 valid family-group name), Oxypeltinae (1), Disteniinae (4), Anoplodermatinae (3), Philinae (1), Parandrinae (2), Prioninae (24), Spondylidinae (5), Necydalinae (1), Lepturinae (8), Lamiinae (80), Dorcasominae (1), and Cerambycinae (107).

Two new species of Onciderini are described and illustrated: Oncideres tavakiliani, from Brazil (Pará), and Clavidesmus egeri, from Peru. Oncideres defectiofasciata Gilmour, 1950 is a junior synonym of O. chevrolatii Thomson, 1868. The following four new country records are reported: O. crassicornis Bates, 1865 (Paraguay); O. glebulenta Martins, 1981 (Paraguay); O. gutturator (Fabricius, 1775) (Venezuela); and O. repandator (Fabricius, 1793) (Peru).

We present an overview of the difficulties sometimes encountered when determining whether a published name following a binomen is available or infrasubspecific and unavailable, following Article 45.6 of the International Code of Zoological Nomenclature (ICZN, 1999). We propose a dichotomous key that facilitates this determination and as a preferable method, given the convoluted and subordinate discussion, exceptions, and qualifications laid out in ICZN (1999: 49-50). Examples and citations are provided for each case one can encounter while making this assessment of availability status of names following the binomen.