Resumo Horismenus camobiensis sp. nov. (Hymenoptera: Eulophidae) é descrita com base em dados morfológicos, moleculares e ecológicos; esta nova espécie Chalcididae atua como hiperparasitoide de Opsiphanis invirae (Hübner, 1818) (Lepidoptera: Nymphalidae) em pupas de seu parasitoide Cotesia invirae Salgado-Neto and Whitfield, 2019 (Hymenoptera: Braconidae). Caracteres diagnósticos morfológicos e moleculares e ilustrações de H. camobiensis são fornecidos.

Abstract Horismenus camobiensis sp. nov. (Hymenoptera: Eulophidae), is described based on morphological, molecular and ecological data; this new species of chalcid wasp acts as hyperparasitoid of Opsiphanis invirae (Hübner, 1818) (Lepidoptera: Nymphalidae) in its parasitoid Cotesia invirae Salgado-Neto and Whitfield, 2019 (Hymenoptera: Braconidae). Diagnoses with morphological and molecular characters and illustrations are provided.

Resumo Lecanodiaspis dendrobii Douglas, 1892 (Hemiptera: Coccoidea: Lecanodiaspididae) e o parasitoide associado Cephaleta sp. (Hymenoptera: Pteromalidae) são registrados pela primeira vez no Brasil. Exemplares dessa cochonilha foram coletados sobre ramos e fustes de Acacia mangium Willd., Leucaena leucocephala (Lam.) de Wit (Fabaceae), Morus nigra L. (Moraceae), Citrus reticulata Blanco (Rutaceae), Tectona grandis L.f. (Verbenaceae), Anacardium occidentale (Anacardiaceae), Annona squamosa L. e Xylopia aromatica (Lam.) Mart. (Annonaceae), em três municípios do Estado de Roraima. Todas as plantas aqui mencionadas são registradas pela primeira vez como hospedeiras de L. dendrobii. Caracteres morfológicos da cochonilha e sintomas das plantas hospedeiras infestadas por esta praga são incluídos neste trabalho.

Abstract Lecanodiaspis dendrobii Douglas, 1892 (Hemiptera: Coccoidea: Lecanodiaspididae) and the associated parasitoid Cephaleta sp. (Hymenoptera: Pteromalidae) are reported for the first time in Brazil. Specimens of this scale insect were collected on branches and stems of Acacia mangium Willd., Leucaena leucocephala (Lam.) de Wit (Fabaceae), Morus nigra L. (Moraceae), Citrus reticulata Blanco (Rutaceae), Tectona grandis L. f. (Verbenaceae), Anacardium occidentale (Anacardiaceae), Annona squamosa L. and Xylopia aromatica (Lam.) Mart. (Annonaceae), in three municipalities of the Roraima state. All plants here mentioned are recorded for the first time as a host for L. dendrobii. Morphological characters of L. dendrobii and symptoms presented by the host plants infested by this pest are included in this work.

In this work we present an output feedback algorithm that solves the trajectory tracking problem in control affine nonlinear systems. This algorithm, is an improvement, for this class of systems, of that of (Mancilla Aguilar et al. 2000a), since it reduces the chattering effect on the control while keeping the original performance. In addition, and via a high gain observer, it deals with discrete output measurements instead of the states, as the original algorithm does.