Ampedus Dejean, 1833 .

“ Ampedus sp. 19” (Table 1) refers to a species described in Ramberg (1979) and uses the number under which he listed the species since Ramberg’s dissertation description is not yet published (and the name is therefore unavailable). Only one Montana specimen of this apparently distinct species exists that was collected in 2010. Ampedus occidentalis Lane (Fig. 1f) specimens from Montana sometimes exhibit a weak or nearly absent apical spot [including “ Ampedus sp. nr. occidentalis ” and “ Ampedus sp. nr. melinus (LeConte) ” in Seibert (1993)], which can indicate other Ampedus species, such as Ampedus evansi (Brown), but all other characters confirm the identity of A. occidentalis . This range of variation in the strength of the apical spot suggests further study is needed. Ampedus nigricans Germar is the correct name for species formerly identified as Ampedus subtilis (LeConte) sensu Brooks (1960) .

The type specimen of A. subtilis belongs to the genus Megapenthes Eschscholtz, 1829 (Ramberg 1979; personal observation), thus making the new combination Megapenthes subtilis (LeConte), as Ramberg never published this observation. The type of M. subtilis (#2444) is located at the MCZC and lacks the anteriorly excavate prosternal sutures of Ampedus . The type specimen does not match any known Megapenthes species in North America but is most similar to Megapenthes angularis LeConte; it differs by being nearly uniformly dark brown in color with two poorly defined, lighter brown maculations on the apical third of each elytron.