Lacus Bonvouloir, 1871

Otto, Robert L., Muona, Jyrki & Córdoba-Alfaro, Jim, 2023, A new genus and sixteen new species of false click beetles (Coleoptera: Eucnemidae) described from the Heredia Province of Costa Rica with several additional records from the Osa Peninsula and Panama, Insecta Mundi 2023 (991), pp. 1-36 : 12

Genus Lacus Bonvouloir, 1871

Diversity and distribution. This group was previously monotypic with the type species, Lacus laticornis Bonvouloir being present in Brazil and French Guiana. The new Central American species is known from only two provinces in Costa Rica and two provinces in Panama.

Diagnosis. Apical margin of frontoclypeal region fairly evenly rounded and less than twice as wide as the distance between antennal sockets; well developed, deep, basally closed lateral antennal grooves present; male protarsomere I simple, without basal sex combs; elytral apices dehiscent; metacoxal plates medially 3.0–6.0 times wider than laterally; frons simple; last visible ventrite either rounded or acute; simple tarsal claws; lateral surfaces of meso- and metatibiae with setae and transverse rows of spine combs ( Muona 2011).

These diagnostic characteristics, especially the presence of a basally closed lateral antennal grooves and obtuse form will distinguish the group from any genera within the tribe Macraulacini .