Contributions to the knowledge of beetles (Insecta: Coleoptera) in the Kaliningrad region. 1. Author Alekseev, Vitaly I. Author Bukejs, Andris text Baltic Journal of Coleopterology 2010 10 2 157 176 journal article 10.5281/zenodo.13204446 1407-8619 13204446 44. HYDROTHASSA MARGINELLA ( LINNAEUS , 1758) Examined material: Recorded from only three localities: Zelenogradsk environs, 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 ).