Amscottia mira (Grönblad) Grönblad (Desmidiaceae, Zygnematophyceae) fue colectada por segunda vez 55 años después de su descripción original. El presente material fue colectado del río Curicuriari (localidad de muestreo 00º 12,454' S, 66º 47,678' W), un río de aguas negras tributario de la orilla derecha del río Negro, Estado Amazonas, norte de Brasil. Los especímenes examinados concordaron íntegramente en su morfología general con la ilustración y descripción original de la especie. La localidad en que los especímenes fueron colectados está ubicada a 49 m s.n.m. La temperatura del agua fue de 26,9º C, elevada acidez (pH 3,7), conductividad relativamente baja (24,37 µS cm-1), buena cantidad de oxígeno disuelto (6,26 mg L-1) y fuerte color (256,56 mg Pt-1).

Amscottia mira (Grönblad) Grönblad (Desmidiaceae, Zygnematophyceae) was collected for the second time 55 years after its original description. The present material was collected from the Curicuriari River (sampling site 00º 12.454' S, 66º 47.678' W), a black water tributary on the right bank of the Negro River, Amazonas State, northern Brazil. Examined specimens totally agreed in their overall morphology with that of the original illustration and description of the species. The locality from which specimens were gathered is located at 49 m a.s.l. The river water temperature was 26.9º C, with high acidity (pH 3.7), somewhat low conductivity (24.37 µS cm-1), good amount of dissolved oxygen (6.26 mg L-1) and strong color (256.56 mg Pt-1).

Stomach contents of Simulium perflavum Roubaud larvae were analyzed and compared with plankton and periphyton collected in five streams, in Central Amazonia (Manaus and Presidente Figueiredo counties), in Sep./Oct.1996 (dry season) and Feb./Mar. 1997 (rainy season). A total of 1,400 last-instar larvae were dissected; the stomach contents were analyzed using different methods: fresh and after oxidation. A total of 87 taxa (algae, diatoms and rotifers) were found in the stomach contents. In each stream, qualitative samples of plankton and periphyton were collected; these were mounted between slides and cover slips. A total of 94 taxa of plankton and 54 taxa of periphyton were collected. One species of Rotifera was present in the stomach contents, plankton and periphyton. Cluster analysis based on species composition of the organisms present in the stomach contents grouped the streams into two major groups, each belonging to a different drainage area. Correlations based on presence/absence of species of microalgae in the stomach contents, plankton and periphyton indicated significant associations (p<0.05) between stomach contents and plankton and between plankton and periphyton (z test); the Sorensen coefficient and cluster analysis corroborate the same associations.