Eustromula validum Click here for a larger view

Diagnosis.--Key characters: Ommatidial size coarse (Fig. 39b); prosternal process expanded apically (Fig. 18); mesal antennal spines present (Figs. 8b, 9b); elytral humeri without tooth at epipleural margin; pronotum with impunctate regions but without longitudinal rugosities or large, evenly-sized punctures; femoral carinae absent; procoxal cavities closed laterally (Fig. 24); femoral apices rounded (Fig. 26); procoxal cavities open posteriorly (Fig. 18); transverse ridges on pronotal disc absent; tibial carinae present (Fig. 22); profemoral shape gradually enlarged (Fig. 37d); meso- and metafemoral shape linear (Fig. 37d); spine of antennomere three acute (Fig. 45a, b); antennomeres three through five approximately length of pronotum; elytral apices with suture dentiform and rounded lateral margin; patches of dense pubescence present on antero lateral areas of pronotum (in males of E. validum, the common species). Length: 20-25 mm.

Distribution and Diversity.--Southwestern United States to México. Two species.

Discussion.--Eustromula fell in the clade containing the other North American genera of Astromula, Enaphalodes, Orwellion, Gymnospyra and Parelaphidion (Fig. 56).

Eustromula resembles in size and proportions Enaphalodes and Astromula. The very short antennomeres (three through five approximately length of pronotum) will differentiate it from Enaphalodes (third through fourth longer than pronotum). The spined antennae will distinguish it from Astromula. Parelaphidion also resembles Eustromula, but has the dense patterns of pubescence on the elytra and pronotum, which is absent from E. validum. Eustromula also lacks elytral apicolateral spines, while Parelaphidion and Enaphalodes have moderate to strong apicolateral spines.