Genus Aegidinus Arrow, 1904
Type species: Aegidium guianensis Westwood, designated by Paulian (1984).
Body small to mid-sized (length 6 mm to 12 mm), reddish brown to dark-brown. Mandibles subsymmetrical. Clypeus with tubercle or horns on anterior margin medially in males, without horn in females. Pronotum variably excavated medially in males, convex to depressed medially in females; anterior margin of pronotum in males with a tubercle or horn medially. Propleurae with carinae separating anterolateral areas from basal area. Scutellum narrowly rounded apically, about 1/15 length of elytra. Elytra convex, with marked humeral umbones, with striae marked with elongated punctures. Wings fully developed. Metepisternon triangular, its posterior angle is rounded to triangular and is situated in the distinct concavity of epipleuron. Anterior tibiae with 3 strong outer teeth in both sexes and with a smaller medial tooth in majority of males. Phallobase tube-shaped with strongly sclerotized ventral side but without differentiation of ventral and dorsal sclerites. Parameres relatively short, with complex shape, asymmetrical in one species, apices without setae.
Species composition. 15 species are known.
Distribution. Members of the genus occur in South America, mostly in Amazon and Guianan moist forest regions to Yungas in the west, and in Trinidad island.
Arrow, G. J. (1904) XXVII. Sound-production in the Lamellicorn Beetles. Transactions of the Royal Entomological Society of London, 52, 709-750.
Colby, J. (2009) Monographic revision of the genus Aegidinus Arrow (1904) and generic phylogeny of the world Orphninae (Coleoptera: Scarabaeidae: Orphninae). Insecta Mundi, 76, 1-41.
Paulian, R. (1984) Les Orphnidae Americains (Coleopteres, Scarabaeoidea). Annales de la Société Entomologique de France (N. S.), 20, 65-92.
Preudhomme de Borre, A. (1886) Descriptions de deux espèces nouvelles du genre Aegidium Westwood suivies de la liste des Orphnides du Musée royal d'histoire naturelle de Belgique. Annales de la Société Entomologique de Belgique, 30, 24-26.
Westwood, J. O. (1845) On the lamellicorn beetles which possess exserted mandibles and labrum, and 10-jointed antennae. Transactions of the Entomological Society of London, 4, 155-180.