Isorhipis

Otto, Robert L., 2024, Three additions to the false click beetle (Coleoptera: Elateroidea: Eucnemidae) fauna in the Nearctic region, Insecta Mundi 2024 (47), pp. 1-14 : 3

Key to the species of Isorhipis in the Nearctic region (modified from Muona 2000)

1. Elytra at least partly yellowish brown or reddish orange, very rarely dark brown................... 2

— Elytra black, body usually black, extremities and sometimes abdomen yellowish red...................................................................... Isorhipis nubila ( Bonvouloir, 1871)

2(1). Tergite VII with strong median keel; pronotal median groove usually restricted to basal half; elytra medially evenly yellowish brown or red, with sides and apical region dark......................... 3

— Tergite VII with poorly developed, low median keel; pronotum with sharp median groove extending usually from base to apical half; elytra with basal half yellowish brown, apical half dark, very rarely entirely dark brown........................................ Isorhipis ruficornis ( Say, 1823)

3(2). Elytra with well-marked, mostly punctate striae; eastern species................................ 4

— Elytral striae weak, without punctures; western species.......... Isorhipis occidentalis Muona, 2000

4(3). Femur infuscate red and black, with dark red tibiae and tarsi; elytra dark reddish orange and black........................................................... Isorhipis bicolor Otto , new species

— Femur, tibiae and tarsi unicolored dark brown; elytra variably dark orange and dark brown...................................................................... Isorhipis obliqua ( Say, 1836)