Contributions to the knowledge of beetles (Insecta: Coleoptera) in the Kaliningrad region. 1. Alekseev, Vitaly I. Bukejs, Andris Baltic Journal of Coleopterology 2010 10 2 157 176   44.    HYDROTHASSA MARGINELLA ( LINNAEUS, 1758) Examined material:  Recordedfrom only three localities: Zelenogradskenvirons, 54°57´11.6´´N 20°29´11.7´´E,  09.V.1998( 1 ex., the Baltic Sea coast, leg. V. Alekseev), 5 km NE Zelenogradsk, 54°58´12.9´´N 20°31´37.3´´E,  11.V.2009(3 exx., wet shore of the Curonian Gulf, on  Caltha palustris, leg. V. Alekseev); Zelenogradsk district, 1 km W Svetlogorsk, 54°56´6.5´´N 20°6´29.4´´E,  14.V.1997( 1 ex., the Baltic Sea coast, leg. V. Alekseev).   Comments:On the territory of the former East Prussia, this species has been reported from Palmnicken [Yantarny], Königsberg [Kaliningrad], Insterburg [Chernyakhovsk], Trempen [Novostroevo in Ozersk district] ( Bercio & Folwaczny 1979). The species is widely distributed across the whole Baltic and Fennoscandian region and has been reported from all territories ( Silfverberg 2004) and also from Belarus(Alexandrovich et al. 1996). The species feeds on Ranunculaceae(  Caltha, Ranunculus). 1997-05-14 2009-05-11 1997-05-14 V, NE, W Svetlogorsk 54.93514 Recorded 1 20.108168 Zelenogradsk district 12 169 2