The aquatic Adephaga of the Makay, central-western Madagascar, with description of two new diving beetle species (Coleoptera, Gyrinidae, Haliplidae, Noteridae, Dytiscidae).

Water beetles of the families Gyrinidae, Haliplidae, Noteridae, and Dytiscidae (aquatic Adephaga) of the Makay in central-western Madagascar were surveyed in three campaigns during the years 2016-2018. A total of 74 species was collected from 62 sampling sites, all except one being newly recorded from the Makay. ( group) and ( group) (Dytiscidae, Copelatinae) are described and their habitus and male genitalia are illustrated.

Four new species of the diving beetle genus Laccophilus Leach, 1815 from Madagascar (Coleoptera, Dytiscidae, Laccophilini).

Four new Laccophilus species are described from Madagascar, three belonging to the L. alluaudi-group (Laccophilus leguyaderi sp. nov.

sp. nov. from the Itremo and Andringitra mountains of central eastern Madagascar (Coleoptera: Dytiscidae: Hydroporinae).

Canthyporus reebae sp. nov. is described from the south-eastern part of the Itremo mountain range and from the Andringitra massif in central eastern Madagascar.