A NEW SPECIES OF PSEUDACTIUM CASEY FROM ARKANSAS (COLEOPTERA, STAPHYLINIDAE, PSELAPHINAE)

The second species of Pseudactium Casey from Arkansas, P. ursum, new s pecies, is described from three male specimens collected in mature dec iduous forest near the Buffalo River, Newton County. Pseudactium ursum resembles P. parabolicum, but differs in anatomical details of the tr ochanters, abdomen, and aedeagus. A modification to a recently publish ed key is provided that allows separation of P. ursum from the ten oth er described species of Pseudactium. Pseudactium ursum is the only kno wn pselaphine species that is precinctive to the Ozark Plateau.