Wed. For those species in Indochina, Paulian (1945) first diagnosed and recorded two species, B. laetus (Westwood, 1852) and B. plagiatus (Westwood, 1848), that were originally described from north India and Ceylon (presently Sri Lanka), respectively. We have examined a number of specimens looking like B. laetus from Thailand and Vietnam. But Paulian’s record of B. plagiatus in our view was based on misidentified specimens of the species described later (B. lao Keith , 2012 from Laos and B. masumotoi Ochi, Kon and Kawahara, 2011 from Cambodia), or to one of our new species described below. Paulian’s material was not traced and the type of B. laetus is probably lost. Actually, specimens of Bolbochromus are not numerous in museum collections, probably due to inappropriate collecting methods. It is likely that the number of known Bolbochromus species will increase in the future when appropriate collecting methods are used. CBR-5884 web Within the Bolboceratinae, adults of Bolbochromus are small (5.8?3.0 mm in length), glossy dorsally, pronotal midline indented, and body usually bicolored with brownish yellow or reddish brown markings on the surface of the pronotum and elytron which may inter/intraspecifically vary in number, size, and shape. The bicolored markings in Bolbochromus species, a character state that is rarely found in bolboceratine beetles, indicates a link with the genus Bolbocerosoma Schaeffer. However, the males of Bolbochromus lack tubercles on their pronotum as in the genus Bolbocerosoma (instead having an indented midline and/or transverse carina). In this paper, we will improve the descriptions of generic characters based on Li et al. (2008), particularly those of the male genitalia (e.g., median lobe) which are of taxonomic and phylogenetic importance. Additionally, we provide an annotated checklist of the genus with the descriptions of three new species from Indochina and the Malay Peninsula, respectively.Materials and methods All specimens used in this study were obtained on loan from the museums (names of curators are in acknowledgments) which are indicated in the type information of new species. Specimens were studied and photographed using a Leica M205C stereo microscope with either a LED5000 MCI or HDI illuminator and a Canon 7D digital camera body. The measurements of specimens, preparation of buy PP58 aedeagus, and external morphological terms used in this paper follow Li et al. (2008). For those of the male genital structures, we employ the terms by D’Hotman and Scholtz (1990).Three new species of Bolbochromus Boucomont (Coleoptera, Geotrupidae, Bolboceratinae)…Systematics Checklist of the genus Bolbochromus Boucomont 1. Bolbochromus catenatus (Lansberge, 1886) Bolboceras catenatum Lansberge 1886: 135. Original combination. Distribution. Sumatra (exact locality unknown); Borneo (exact locality unknown); Brunei (Boucomont 1914); Java (Boucomont 1914). 2. Bolbochromus celebensis Boucomont, 1914 Bolbochromus celebensis Boucomont 1914: 347. Original combination. Distribution. Celebes (type locality: Toli-Toli). 3. Bolbochromus hirokawai Ochi, Kon Kawahara, 2010 Bolbochromus hirokawai Ochi, Kon and Kawahara 2010: 97. Original combination. Distribution. Negros Is. (type locality: Mt. Canla-on, Philippines). 4. Bolbochromus laetus (Westwood, 1852) Bolboceras laetus Westwood 1852: 27. Original combination. Distribution. Sri Lanka (exact locality unknown); Vietnam; Laos; S. China (Guizhou) (Paulian 1945, see our comment in introduction).Wed. For those species in Indochina, Paulian (1945) first diagnosed and recorded two species, B. laetus (Westwood, 1852) and B. plagiatus (Westwood, 1848), that were originally described from north India and Ceylon (presently Sri Lanka), respectively. We have examined a number of specimens looking like B. laetus from Thailand and Vietnam. But Paulian’s record of B. plagiatus in our view was based on misidentified specimens of the species described later (B. lao Keith , 2012 from Laos and B. masumotoi Ochi, Kon and Kawahara, 2011 from Cambodia), or to one of our new species described below. Paulian’s material was not traced and the type of B. laetus is probably lost. Actually, specimens of Bolbochromus are not numerous in museum collections, probably due to inappropriate collecting methods. It is likely that the number of known Bolbochromus species will increase in the future when appropriate collecting methods are used. Within the Bolboceratinae, adults of Bolbochromus are small (5.8?3.0 mm in length), glossy dorsally, pronotal midline indented, and body usually bicolored with brownish yellow or reddish brown markings on the surface of the pronotum and elytron which may inter/intraspecifically vary in number, size, and shape. The bicolored markings in Bolbochromus species, a character state that is rarely found in bolboceratine beetles, indicates a link with the genus Bolbocerosoma Schaeffer. However, the males of Bolbochromus lack tubercles on their pronotum as in the genus Bolbocerosoma (instead having an indented midline and/or transverse carina). In this paper, we will improve the descriptions of generic characters based on Li et al. (2008), particularly those of the male genitalia (e.g., median lobe) which are of taxonomic and phylogenetic importance. Additionally, we provide an annotated checklist of the genus with the descriptions of three new species from Indochina and the Malay Peninsula, respectively.Materials and methods All specimens used in this study were obtained on loan from the museums (names of curators are in acknowledgments) which are indicated in the type information of new species. Specimens were studied and photographed using a Leica M205C stereo microscope with either a LED5000 MCI or HDI illuminator and a Canon 7D digital camera body. The measurements of specimens, preparation of aedeagus, and external morphological terms used in this paper follow Li et al. (2008). For those of the male genital structures, we employ the terms by D’Hotman and Scholtz (1990).Three new species of Bolbochromus Boucomont (Coleoptera, Geotrupidae, Bolboceratinae)…Systematics Checklist of the genus Bolbochromus Boucomont 1. Bolbochromus catenatus (Lansberge, 1886) Bolboceras catenatum Lansberge 1886: 135. Original combination. Distribution. Sumatra (exact locality unknown); Borneo (exact locality unknown); Brunei (Boucomont 1914); Java (Boucomont 1914). 2. Bolbochromus celebensis Boucomont, 1914 Bolbochromus celebensis Boucomont 1914: 347. Original combination. Distribution. Celebes (type locality: Toli-Toli). 3. Bolbochromus hirokawai Ochi, Kon Kawahara, 2010 Bolbochromus hirokawai Ochi, Kon and Kawahara 2010: 97. Original combination. Distribution. Negros Is. (type locality: Mt. Canla-on, Philippines). 4. Bolbochromus laetus (Westwood, 1852) Bolboceras laetus Westwood 1852: 27. Original combination. Distribution. Sri Lanka (exact locality unknown); Vietnam; Laos; S. China (Guizhou) (Paulian 1945, see our comment in introduction).