This paper provides a revision of the three smallest subgenera of Deltochilum, all endemic to the Atlantic Forest of South America. Deltochilum (Euhyboma) and D. (Rubrohyboma) are monospecific taxa, composed of D. brasiliense (Castelnau, 1840) and D. rubripenne (Gory, 1831), respectively, whereas D. (Parahyboma) is composed of two allopatric species, D. furcatum (Castelnau, 1840) and D. granulosum Paulian, 1933. Lectotypes for D. brasiliense and D. rubripenne are designated. Each species is analyzed as follows: a detailed literature review, a diagnosis, description, illustrations of key morphological characters, list of material examined, and geographic distribution. An improved identification key to the subgenera of Deltochilum is presented.

The South American species of Pseudocanthon Bates, 1887 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini) are reviewed. In this work, 10 valid species and two subspecies are recognized for the genus. Among these species, five are recorded in South America, including three new species: P. perplexus (LeConte, 1847), P. xanthurus (Blanchard, 1847), P. vazdemelloi new species, P. pantanensis new species, and P. chaquensis new species. A lectotype is designated for P. xanthurus (Blanchard, 1847). In this revision, each species is analyzed as follows: a detailed literature review, an identification key for the South American species, a diagnosis, descriptions, illustrations of key morphological characters, list of examined material, and geographic distribution.