Alderia modesta (Lovén) and Limapontia depressa Alder & Hancock in the brackish waters of the Dutch coast

The following records of two species of Sacoglossa in the Netherlands induced us to some observations and to the study of the literature, the results of which are given here. Alderia modesta (Lovén) 1) many specimens on Vaucheria patches on the mud along the bank of the Nieuwe Waterweg, at the N. coast of the Island of De Beer, opposite Hoek van Holland, Aug. 24 1939, leg. S. J. Geerts and C. O. van Regteren Altena. 2) many specimens on Vaucheria in tidal creeks of the ”Schorre”, called the ”Rietmoeras”, at the SE. coast of the Island of De Beer, Aug. 24 1939, leg. S. J. Geerts and C. O. van Regteren Altena. 3) many specimens at the same localities, Sept. 29 1939, leg. H. Engel and S. J. Geerts. Limapontia depressa Alder & Hancock 4) some few specimens on fine algae in small pools with water in a creek of the ”Schorre” in the Northern Sloe (province of Zeeland), between the railway-embankment and Caland-schorre, Sept. 1 1939, leg. C. Brakman. Limapontia depressa Alder & Hancock, var. pellucida Kevan 5) many specimens, locality and date as 2) 6) several specimens, locality exactly as 2), date as 3).