Received 23-XI-2000. Accepted 25-II-2001.

Ulmeritoides misionensis Domínguez, 1995, a mayfly previously known to occur only in Argentina, is for the first time recorded in Brazil, based on four nymphs from Rondônia State, Amazonic Region: one male and one female from Tachi, Travessia Paú, Cabeceira do Rio Candeias (10 o 30’ S; 63 o 15’ W), 14/VIII/1985 (in Universidade Federal do Rio de Janeiro), and two females from Igarapé Ribeirão (10 o 15’ S, 65 o 16’ W, 120 m), 09/VIII/1985 (in Instituto Nacional de Pesquisas da Amazônia). This is the third nominal species of Ulmeritoides known to occur in Brazil, after U. uruguayensis (Traver, 1959) and U. patagiatus (Thew, 1960), occuring in Santa Catarina State. Reference: Domínguez, E. 1995. Cladistic analysis of the  UlmeritusUlmeritoides group (Ephemeroptera, Leptophlebiidae), with descriptions of five new species of Ulmeritoides. J. New York Entomol. Soc. 103: 15-38.

Elidiomar Ribeiro Da-Silva ¹ and Maria José Nascimento Lopes ²

1 Laboratório de Insetos Aquáticos, Departamento de Ciências Naturais, UNI-RIO, 20211-040, Rio de Janeiro, RJ, Brasil. Associated researcher to Laboratório de Entomologia, UFRJ. E-mail: elidiomar@uol.com.br