Rediscovery of the Hawaiian endemic bark beetle Xyleborus pleiades Samuelson, 1981 on Moloka'i, with records of three new exotic bark beetles for the island (Coleoptera: Curculionidae: Scolytinae: Xyleborini).
During the course of a targeted bark beetle survey of the Hawaiian Islands, insect sampling undertaken in native forest biotopes on Moloka'i island revealed the presence of one native and three exotic species of xyleborine bark beetles (Coleoptera: Curculionidae: Scolytinae: Xyleborini) hitherto not recorded from the island. We present detailed new island records for these species, which include the second record of Xyleborus pleiades Samuelson, 1981, an endemic Hawaiian species not recorded in over 50 years, and previously known only from two specimens from the island of Maui. The three newly recorded introduced species are widespread pantropical beetles of actual or potential pest status: Xyleborus affinis Eichhoff, 1867, Xyleborinus saxesenii (Ratzeburg, 1837), and Xylosandrus crassiusculus (Motschulsky, 1866). The importance of the records is briefly discussed, and all newly recorded species are illustrated in colour photographs.