Sixeonotopsis crassicornis Carvalho and Schaffner has remained obscure since its 1974 description from Texas and has been known only from the type locality. It is newly recorded from Arkansas (two locales) on branched foldwing (Dicliptera brachiata [Pursh] Spreng.; Acanthaceae), the first plant documented as a host of this bryocorine mirid of the tribe Eccritotarsini. Branched foldwing, known from the type locality of S. crassicornis (Palmetto State Park, Gonzales County, TX), is suggested to have been the source of specimens used in the original description. Collection data are given for a recently identified specimen of the plant bug collected in 1906 from Victoria, Texas. Notes on the bug's habits, habitat, and seasonality are included, as well as a diagnosis, redescription, and discussion of its taxonomic relationship to other North American eccritotarsine Bryocorinae.