The rediscovery of some of the lost collection of Monsieur A. David-Beaulieu from Laos is reported. Notes are given on 22 selected forms and a list is appended of the type specimens and topotypical material in the collection. One species, Acrocephalus concinnens, is reported from Indochina for the first time and several forms are reported or confirmed for the first time for either North or Central Laos.