It has been suggested that palms of the genusArenga(Arecales: Arecaceae) or forms close to it were distributed in the Eocene of North America and Europe. Records of Metrioxenini (Belidae), which are monophages on these palms, confirm this assumption. A new species,Succinometrioxena andrushchenkoiLegalov, sp. n. from Baltic amber is described. The new species differs fromS.poinariLegalov, 2012 in the smaller body sizes, elytral punctation larger than the distances between them, and a rostrum weakly curved in females. It is distinguished fromS.bachofeniLegalov, 2013 andS. attenuataLegalov et Poinar, 2020 by the forehead lacking horn-like tubercles on either side of the eyes. A description of male ofS.poinariwas herein compiled for the first time. A list and key to fossil Metrioxenini were given. The modern and fossil distribution of the tribe Metrioxenini and Arenga palms was shown.