Rhacognathus americanus

The adults are large (9–11 mm) predaceous stinkbugs, usually dark brown black mottled with dull yellow. Historically it has been rarely encountered, therefore nothing about its life history is known.^[4][5]

There were less than 40 verifiable sightings of this species in the 20th century, mostly in the Great Lakes region and the Prairies. No individual has been collected or seen since 1966, despite the increased use of citizen science projects such as iNaturalist and recent stinkbug monitoring projects (largely to target the brown marmorated stink bug). The species is likely extirpated from Ontario, and may even be extinct.^[4]