The adventive species, Hylis olexai (Palm) (Coleoptera: Eucnemidae: Melasinae), a common, wide¬spread species found throughout much of Western and Central Europe, are documented for the frst time as new country, provincial and state Records in both Canada (Ontario and Quebec) and the United States (Connecticut, Illinois, Maine, Massachusetts, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, West Virginia and Wisconsin). Adults of H. olexai and Hylis frontosus (Say) are redescribed and are compared with other Hylis des Gozis species in the Nearctic Region. Larvae of H. olexai are redescribed and illustrated. Te re-evaluation of Hylis spp. material from CMNH and the CNC also led to the discovery of Hylis delicatus Otto, Bédard and Muona, new species, also newly recorded for the frst time in Canada (Ontario) and the United States (Delaware, New Jersey, New York and Ohio). Four of the six Nearctic Hylis species (Hylis frontosus, H. terminalis (LeConte), H. olexai and H. delicatus new species) are imaged, highlighting essential character states to facilitate improved diagnosis in conjunction with a new identifcation key. Diagnosis of female H. olexai and H. delicatus new species, as it relates to Hylis irvinei Muona and H. terminalis, along with the success of adventive eucnemid species establishment in the Nearctic region, are discussed. A new country record for H. frontosus in Canada (Quebec), along with new state records for H. frontosus in Arkansas and Virginia, are noted.
Otto et al. (2026) studied this question.