Helluomorphoides ferrugineus

Diagnosis
The slender antennae, slender terminal segment of the maxillary palpus and the relatively broad and shallow elytral striae serve to distinguish this species from the other members of the genus. H. ferrugineus can be most readily confused with texanus, but in the greater part of the area where the two are sympatric the discal elytral striae of the former are triseriately punctate, whereas those of the latter are biseriately punctate.

Distribution
—Specimens of this species which occur on the Atlantic Coast westward to the Edwards Plateau in Texas invariably have the elytral striae triseriately punctate. To the south and west, the elytral punctures are usually finer and less numerous, and in some specimens are arranged biserially. This persists across northern Mexico, and into southern Arizona and New Mexico. The type specimen of Helluomorpha languida (Brownsville, Texas) falls in the latter category. The western Texas sample (Fort Davis-Chisos Mountains-Alpine) seems to be intermediate between the two poorly defined conditions.

Arizona, New Mexico, Texas (Type), Mexico

Biology
Howard Topoff observed Helluomorphoides ferrugineus running in raiding and migrating coluns of army ant Neivamyrmex nigrescens in Arizona. The adult beetles were eating larvae and pupae of ants.