Hydraenidae of Madagascar (Insecta: Coleoptera) Author Perkins, Philip D. text Zootaxa 2017 2017-11-03 4342 1 1 264 journal article 31639 10.11646/zootaxa.4342.1.1 15799d2a-1968-4874-8100-452597d4e26b 1175-5326 1041066 2ACD54D2-3487-432D-9323-EEC131FE2E64 Hydraena discicollis Fairmaire , nomen dubium Hydraena discicollis Fairmaire 1898b : 469 . Through the kindness of Antoine Mantilleri I was notified that the type specimen of H. discicollis was no longer affixed to the card. The pin with the card has the following labels: "Madag Perrier; Hydraena discicollis Fm. Madag ; MUSEUM PARIS MADAGASCAR PERRIER DE LA BATHIE COLL. LEON FAIRMAIRE 1906." No potential syntypes were found. Fairmaire (1898b: 468–469) described four species of Hydraena . The original description of the first of the four ( H. dilutipes ) is written in Latin. The second ( H. impressicollis ) and the third ( H. borbonica ) are written in French, comparing them to H. dilutipes . The fourth species described is Hydraena discicollis , and here Fairmaire returns to a Latin description, which differs markedly in wording from the description of H. dilutipes . Significantly it states that the head is "capite nigro, paulo metallico" and the prothorax is "fulvo-lutoso, disco transversim infuscato." After the Latin description, Fairmaire comments that the pronotum is "ayant de chaque cote, au milieu une forte impression arrondie." I know of no species of Hydraena that has the combination of a black metallic head and brownish pronotum and elytra, and impressions as noted. This leads me to surmise that Fairmaire was describing a specimen of Aulacochthebius or Ochthebius , not Hydraena . In light of the foregoing, it is necessary to treat the name Hydraena discicollis Fairmaire as a name of unknown or doubtful application, that is, a nomen dubium as per the ICZN.