Captured, photographed and released. This is the dorsal side which is hardly seen in the field, but a key in seperating genera: Buenoa has a pale-colored scutellum, while Notonecta has a black scutellum (Arnett, p. 280 (1)).

Looking at the markings on the wings, this is most likely N. irroratus (Besprinkled Backswimmer?). The University of Michigan mentions the red and black wings as a distinguishing feature.