Small grayish beetle on Solidago gigantea inflorescence in full flower. Moderately shortened elytra. Ca 100-200 present on 1 Solidago gigantea plant (and not seen on others). Collected. Flying readily when disturbed. Level, sunny floodplain community dominated by introduced grasses, with occasional native herbs. Late afternoon, light breeze, sunny, 70 F. Legumes within 500 m of the collection site included Glycyrrhiza lepidota, Medicago sativa, and several species of Astragalus (primarily A. bisulcatus, A. canadensis, and A. crassicarpus).

Elevation ca 4000 feet. Disturbed riparian corridor on stream restoration site within a patchwork of native and non-native grassland.

Keyed to Acanthoscelides in Kingsolver 2004 and attempted to key to species. Characters included the integument of the body and appendages entirely dark except for reddish on the basal antennomeres; presence of a lateral carina on the outer face of the metatibia; the elytral vestiture uniform (confirmed with my blurry field photos when I collected; some pubescence has apparently since rubbed off of the elytra); and the first denticle of the pecten notably larger than the others. The large first denticle seems unlike any of the "expected" species for Montana with these other characters. I hope to revisit in the spring when I have access to a higher-powered scope; however, if someone with lots of experience with this group would like me to send them the specimen, I would be happy for someone else to identify it.