Peristicta guarellae sp. nov. (holotype: Brazil, Parana State, Exc. 399/col. 3, stream in km 50 of Curitiba-Ponta Grossa route [BR 376], about 25 degrees 2008 S, 49 degrees 5115 W, 21 November 1971, N. D. Santos leg., deposited in the Collection of Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil) is described and illustrated. An identification key for males of Peristicta (excluding P. lizeria Navas), comparisons and comments on other species of the genus are presented.