Water bug seined from shallow water of pond - the same pond in which I also collected N. undulata on the same date. Dark transverse bar across corium. Collected. Pond created in winter 2020-2021 from old, incised stream channel by heavy equipment during stream restoration work. Unusually warm evening about 5 days after 1 inch of snow fell, now melted. Dusk, high clouds, 66 F to 62 F, gusty breeze varying from light to fresh.

Elevation ca 4000 feet. Disturbed riparian corridor on stream restoration site within a patchwork of native and non-native grassland.

Keyed to species using the key to common Notonecta in Slater & Baranowski 1978. In Montana this should be the only Notonecta species with the fourth visible sternite with a central area bare of hairs on the keel; according to Hungerford 1933, N. insulata (the other widespread North American species with this character) is distributed in Canada and the northern U.S. east of the 100th meridian. This specimen also matched all of the characters of N. kirbyi vs. N. insulata in the Slater & Baranowski key.