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Rishiri Island is located off the northwest coast of Hokkaido, Japan. Faunistic research of the island is important to clearly elucidate the faunal composition of the Palearctic Far East. Numerous faunistic studies on beetles, such as Carabidae, have been conducted for this island, however, there are few records for cucujoid beetles. As a result of the research herein, including field, museum specimen, and literature research, conducted by the authors in 2019, four kateretid beetle species and 38 nitidulid beetle species have been recorded from the island. Among these beetles, Epuraea silacea is a first report from Japan. Additionally, two kateretid and 23 nitidulid beetle species are newly recorded from Rishiri Island. [ABSTRACT FROM AUTHOR]

The olive weevil, Pimelocerus perforatus（Roelofs）（Coleoptera: Curculionidae）, is a serious pest of olive cultivation in Japan. Although male and female adults of weevils are generally very similar, we established a simple method for discriminating the sex of olive weevil adults based on external morphology. We found that the first through fourth abdominal ventrites of the females were longer than those of the males, while the fifth abdominal ventrite was shorter. Moreover, the length of the lateral margin of the second abdominal ventrite was markedly different between the sexes. As a result, the ratio of the medial length of the fifth abdominal ventrite to the lateral margin length of the second abdominal ventrite was distinct between the sexes in both wild and laboratory-reared populations of P. perforatus, i.e., the ratio was larger than 0.60–0.65 in females but smaller in males. In addition to this characteristic, the structure of the medial part of the first abdominal ventrite differed between the sexes: it was depressed in the middle in males but inflated in the middle in females. Based on these morphological differences, males and females of the olive weevil were successively discriminated from each other. [ABSTRACT FROM AUTHOR]