Diagnosis.--Key characters: Ommatidial size coarse (Fig. 39b); Prosternal process not planar, apex expanded (Fig. 18); mesal antennal spines present (Figs. 8b, 9b); pronotum with impunctate regions present; pronotum without transverse ridges, longitudinal rugosities, or large, uniformly-sized, confluent punctures; femoral carinae absent; procoxal cavities closed (Fig. 24); femoral apices rounded (Fig. 26); elytra without dense, golden or silver pubescence, with only sparse long, erect hairs; procoxal cavities open posteriorly (Fig. 18); tibial carinae present (Fig. 22); femora gradually enlarged (Fig. 37c); spine of antennomere three blunt (Fig. 28); lateral projections into mesocoxae from mesosternum absent (Fig. 20); elytral apicolateral spines absent; elytral sutural spines weak; elytra with unique, large, coarse punctures, denser towards base; peripheral pronotal calli well developed; antennomeres linear, not expanded at apices (Fig. 22); body not very narrow. Length: 12-14 mm.
Distribution and Diversity.--Southwestern United States to México. Monotypic.
Discussion.--Although Linsley (1936) felt that Stenelaphus was closely related to Stenosphenus, in my analysis the two genera were not shown to be closely related (Figs. 50, 56). Stenelaphus fell as sister taxon to the clade containing other primarily southwestern United States taxa including Enaphalodes, Orwellion, Eustromula, and Gymnospyra (Fig. 56) based on the implied weighting phylogenetic analysis.
Stenelaphus is easily recognized by the blunt spine of the third antennomere (rarely acute), elytra with only sparsely scattered long, flying hairs, and unique, coarse elytral punctation.