Nematodes Berthold, 1827

Otto, Robert L., 2021, A review of the Nearctic species of Nematodes (Coleoptera: Eucnemidae: Macraulacinae: Nematodini) with a description of one new species, Insecta Mundi 2021 (881), pp. 1-19 : 2

Genus Nematodes Berthold, 1827

Diagnosis. Apical margin of frontoclypeal region feebly trilobed and more than twice as wide as the base; antennal grooves absent; male protarsomere I simple with basally curved sex combs; tarsal claws simple; tarsomere IV excavate-emarginate; metacoxal plates medially 3.0–6.0 times wider than laterally; last visible ventrite strongly produced; lateral surfaces of meso- and metatibiae with setae and transverse rows of spine combs; metathoracic episterna parallel-sided; male aedeagus dorsoventrally compressed, with laterally attached secondary lateral lobes; median lobe simple, with moderately and narrowly bifurcate apices; lateral lobes simple, entire; flagellum simple ( Muona 1993, 2011; Otto 2016).

These diagnostic characteristics, especially the presence of excavate-emarginate tarsomere IV and parallelsided metathoracic episterna will distinguish the group from any genera within the tribe Nematodini . The new identification key will largely feature the overall length of the femoral ridge at the base of the hypomera where the femur rests when legs are reposed as a means to diagnose each species present in this region.