Diagnosis.--Key characters: Ommatidial size coarse (Fig. 39b); prosternal process not planar, expanded at apex (Fig. 18); mesal antennal spines present (Figs. 8b, 9b); pronotal impunctate regions present; pronotum without rugosities, transverse ridges, or large, uniformly-sized punctures; femoral carinae absent; procoxal cavities closed laterally (Fig. 24); femoral apices rounded (Fig. 26); elytra without dense silver or golden pubescence, nearly glabrous except for long flying hairs; procoxal cavities open posteriorly (Fig. 18); tibial carinae present (Fig. 22); femora varying from gradually enlarged to clavate (Fig. 37b, c); pronotum and head without dense yellow or white pubescence; antennae carinate (Fig. 45b); spine of antennomere three acute (Figs. 45b); antennomere three about two-thirds length of pronotum (Fig. 46b); lateral projections from mesosternum into mesocoxae present (Fig. 21); antennomeres linear, not expanded at apices (Fig. 22); lateral pronotal tubercles present and acute; median pronotal callus and peripheral pronotal calli present; elytral apices truncate to moderately spinose. Length: 15-18 mm.
Distribution and Diversity.--Southwestern United States (Arizona) to México. Two species.
Discussion.--The implied weighting phylogenetic analysis resulted in the placement of Pseudoperiboeum at the base of a large clade of primarily North American genera (Fig. 50). It fell as the sister taxon to the anomalous "Elaphidion" elegans, but more analysis needs to be undertaken to fully understand relationships at this level of the phylogeny.
The well-developed median and peripheral pronotal calli, acute lateral pronotal tubercles, and long flying hairs scattered over the otherwise glabrous integument, distinguish this genus from others.