Differences among the metapleural glands of four female castes of Atta bisphaerica Forel, 1908, A. capiguara Gonçalves, 1944 and A. sexdens rubropilosa Forel, 1908 were examined by scanning electron microscope. There were no differences in gland size between the same castes of these species, although the opening gland in A. sexdens rubropilosa had been twice as large as A. bisphaerica. The relative size and functional significance of the metapleural gland among different castes is discussed and similarities between these and the other Formicidae till now studied is presented.

A new methodology to evaluate the effect of insecticides on Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in flooded rice (Oryza saliva) was tested. Artificial infestations with fall armyworm larvae (3rd -4th instars) on rice field plots, fenced by metallic cages was used. Larval mortality was evaluated 48 hours after insecticide application by flooding the rice field and counting the floating surviving insects. Lambdacyalothrin CE (7.5 g/ha) and permethrin CE (25 g/ha) provided high larval control (> 95 %). Cifluthrin CE (7.5 g/ha) and deltamethrin CE (2.0 and 2.5 g/ha) caused less mortality (< 70%). The advantages of this new methodology are discussed.