The aim of this paper is to present the analysis of sexual morphological differences observed in 5th instar nymphs of the following species: Panstrongylus megistus; Rhodnius neglectus; Triatoma brasiliensis; T. infestans; T. matogrosensis and T. tibiamaculata. Male and female nymphs were examined and photographed with a Scanning Electron Microscope. The 9th segment dimensions of dorsal and ventral faces were determined through a Profile Projector. Results and statistical analysis showed significant differences: the 9th sternite is significantly broader in male than female nymphs, while in five species; tergites in female nymphs are broad and in male are narrow

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This paper describes the drawing, construction and optimization of a device, which can be used to obtain single crystals of different metallic materials with melting point from 550 to 1050 o C. Components of ease obtaining and of low cost were used. The device was based on the modified Bridgman technique and it was used to obtain single crystals of copper-based alloys. The temperature axial profiles and a difference less then 1% in the temperature between the wall and the center of the ceramic tube in the critical region for obtaining single crystals of good quality indicated that the oven presents a good thermal stability. Single crystals of CuZnAl and CuAlAg alloys of good quality were growth and characterized using optical microscopy and Laüe X-ray back reflection.

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The electrochemical behavior of Cu-(0.5-13 wt.%)Al alloys in K 2 SO 4 0.5 mol dm -3 (µ= 1.5 M, pH 2-5) was studied using open-circuit potential (E oc ) measurements and polarization curves, in order to know the conditions of copper oxides formation, influence of Al concentration and solution pH on the electrode processes. The opencircuit potential measurements with time indicated that the E oc decreases with the Al content, due to the lower Al potential compared to Cu. The electrode potentials decrease ca. 20 mV per unity of solution pH as increase pH of the solution. The polarization curves showed changes with the increase of Al concentration. For alloys with up to 3 wt.%Al the obtained Tafel anodic coefficient was 40 mV/decade for low potentials region (E < -320 mV) and 130 mV/decade for the other region (-320 < E/mV < -250), indicating that up to this concentration there is no considerable change in the electrochemical behavior of the alloys, when compared to pure Cu. For alloys with an Al content from 8 to 13 wt.% the Tafel anodic coefficient was 60 mV/decade. No influence of the solution pH on the Tafel anodic coefficient was observed. IntroduçãoAs ligas de cobre vêm sendo utilizadas desde a antigüidade em função de suas boas propriedades de resistência à corrosão em vários meios, alta condutividade térmica e elétrica e facilidade em uso mecânico. Sabe-se que a adição de Al ao