A new species of the genus Rachicerus Walker (Diptera: Xylophagidae), with notes on Messias Carrera's 1940 and 1945 types housed in Museu de Zoologia, Universidade de São Paulo and in Instituto Oswaldo Cruz, Rio de Janeiro, Brazil.

Five Rachicerus species are recorded in Brazil: Rachicerus lanei Carrera, 1940, R. oliverioi Carrera, 1940, R. lopesi Carrera, 1940, R. marcusi Carrera, 1940 and, R. shannoni Carrera, 1945. Here I describe a new species Rachicerus carrerai sp. nov. based on three male specimens from Brazil (Amazonia and Mato Grosso do Sul) and Colombia (Chocó). The new species is distinguished from the other known species by the antenna with bipectinate flagellomeres, a character only known from fossils. The conditions of the Messias Carrera's type specimens are discussed and a key for the Brazilian species of Rachicerus is provided.