In 1954, 1 visited the laboratory of Professor Newton Santos in the National Museum in Rio de Janeiro for training in dragonfly taxonomy, and took with me specimens of the "monotypic” genus Elga, collected at At, ucena. Minas Gerais. This species proved to be different from another in the Museum collection, collected in Pirassununga, Sao Paulo, which had been identified as Elga leptostyla, Ris, 1911. The species from Minas Gerais was described as Elga santosi in a paper in which the species believed to be E. leptostyla Ris, was also described and illustrated (A.B.M. MACHADO, 1954, Re via. hrasil. Biol. 14: 303-312). During a visit to the Paris Museum I had the opportunity to study the holotype of E. leptostyla Ris, which is deposited in Martin's collection there. The specimen was in very good condition and corresponded well to the description given by RIS (1911, Colins zool. de Selys-Longchamps 12: 385-528), except for the fact that the subtriangle has two cells in the left wing whereas the description stated that it is free in both wings, as shown in Ris's fig. 245. The study of this type showed clearly that the species I had described as E. santosi was in fact E. leptostyla Ris and what I had ” redescribed" as E. leptostyla was actually a new species which, therefore, remains unnamed. In view of this fact Elga santosi Machado, 1954 should be regarded as a synonym of Elga leptostyla Ris, 1911 and the new species is now named Elga newtonsantosi nom. nov. after my master Professor NewtonDiasdos Santos, the father of Brazilian odonatology (A.B.M. MACHADO & J.M. COSTA, 1990, Odonalologica 19: 297-308). The description and the illustrations of this species (under E. leptostyla) contained in my paper of 1954 (MACHADO, 1954, op.cit.) are accurate and allow for its easy separation from true E. leptostyla which is redescribed in the same paper (under E. santosi). I designate now a male specimen in my collection (RibeirSo S. Vicente, Pirassununga, Sao Paulo, I/15-XII-1948, N. Sanlos & J.P. Machado leg.) as a holotype for the new species. The other 12 male and a single female specimens, mentioned (under E. leptostyla) in my paper of 1954, all collected at the same locality as the holotype, should be regarded as paratypes. They are deposited in the collection of the National Museum, Rio de Janeiro, (10 6, 1 2) and in my own collection (2 6).