3à of the new sp., described and illustrated here, were collected in January. 1979. not far from the Iguazù waterfalls. Argentina, along with numerous A. gracile (Ramb.). 6 holotype. I d paratype: nr. DestacamentoCataratas. Iguazu, Misiones, Argentina; Jan. 20. 1979; I d paratype: same locality; Jan. 31. 1979. The new sp. is referable to the viridescens-group of J.W. LEONARD (1977. Mixc. Puhlx Mux. Zool. Unix. Mich. 153: 1-154, pis. 1-19).