Simple SummaryInsects of the Nepomorpha infraorder live in various environments—some are associated strictly with water and some are mostly terrestrial. In this study, we examined specimens from the aquatic Corixidae and two riparian families—Ochteridae and Gelastocoridae. Apart from the differences in general leg morphology (legs adapted for swimming in Corixidae and for walking in Ochteroidea), there were eight types of sensilla found on the legs. From those, mechanosensilla displayed the most observed variability. The leg sensilla of Nepomorpha had not been studied until now.AbstractThe aim of this study was to analyze morphological types and arrangement of the leg sensilla of Corixidae, Ochteridae and Gelastocoridae, in relation to their various habitats. The leg sensilla of four species of Corixidae, six of Gelastocoridae and two of Ochteridae were studied. Eight main types of sensilla with six subtypes of sensilla trichodea and four subtypes of sensilla chaetica were found and described. The greatest variability was observed among mechanoreceptive sensilla. The study showed differences in the shape of the legs between strictly aquatic and terrestrial taxa. It is the first attempt to describe leg sensilla among nepomorphan taxa.