Dr P. Wagenaar Hummelinck entrusted me with the identification of the mosquitoes he collected during his trips to the West Indies in 1936—1937 and 1948—1949. Although dr Hummelinck told me that it was not his intention to catch representative material, the present collection is of particular hygienic and biological interest as some mosquitoes were found on islands from which they had not been reported before. This paper deals with 16 species: Wyeomyia celaenocephala — Curaçao, Anopheles pseudopunctipennis pseudopunctipennis — Margarita, Curaçao, Aruba, Anopheles albimanus — St. Martin, Aëdes taeniorhynchus — Curaçao, Saba, Dog Island, Aëdes aegypti — Curaçao, Aruba, St. Barthélemy, St. Martin, Haemagogus anastasionis — Curaçao, Aruba, Psorophora confinnis — Bonaire, Curaçao, Psorophora pygmaea — St. Martin, Deinocerites cancer — St. Martin, Culex erraticus — Curaçao, Culex americanus — St. Eustatius, St. Martin, Culex bahamensis — St. Eustatius, St. Barthélemy, St. Martin, Culex maracayensis — Curaçao, Culex chrysonotum — Suriname at Zanderij, Culex coronator — Venezuela near La Guaira, Culex nigripalpus — Bahamas, on South Bimini, and Culex quinquefasciatus — Bonaire, Curaçao, Aruba, St. Eustatius, St. Martin.