Cremastocheilus robinsoni

One of about thirty-five species of myrmecophilous Cremastocheilus. The host ant is unknown.

Identification
DIAGNOSIS. Head with front angularly produced, very abruptly declivous to strongly reflexed clypeal margin, clypeus nearly half as long as pronotum, medially carinate, with large quadrate tomentose spot at each side of carina; dorsal faces of mesepimera large, shallowly concave; pronotum widest at posterior third, disc coarsely, densely punctate, posterior angles acutely triangular, pointed; elytral disc annularly punctate, punctures elongate.

This species is only remotely related to the other members of Cremastocheilus. Its salient characters are the front of the head which is produced and angulate, and the large, concave, meso-episternum. The prothorax resembles somewhat that of C. nitens but the side margins are not serrated and the front angles are more produced. In C. nitens the posterior declivity is more pronounced.

Distribution
Arizona, Mexico (Durango).

Habitat
Common ant host is unknown.

Nomenclature
Holotype female in the collection of Mark Robinson, collected at Lerdo, Durango, Mexico (Wickham).

Description
Rather large, robust; uniform reddish-brown throughout. Head with vertex shallowly, sparsely punctate, punctures separated by about their own widths, front projecting outward from eyes, parallel with reflexed margin of clypeus,, pointed medially, lower anterior portion abruptly descending to clypeal margin upper portion deeply, densely, irregularly punctate, lower portion with large impunctate opaque areas laterally, the lower and lateral portion tomentose; reflexed clypeal margin nearly as wide as head, impunctate; antennal scape large, concave; mentum cupuliform, posterior margin produced medially. Pronotum about three-fourths as wide as elytra, widest at basal third, sides irregularly rounded anteriorly, anterior angles bluntly produced, inner depression rather deep, posterior angles noduliform and produced outward; an elevated area at basal third of surface, gradually descending to anterior margin, elevation portion densely covered with large shallow punctures, coalescent or separated by about one-sixth their own widths, becoming sparse anteriorly to impunctate area along margin. Elytra elongate, robust, side margins subparallel; surface punctate with elongate ring-like punctures, punctures separated laterally by about their own widths; meso-episternum prominent above, middle shallowly concave. Beneath glabrous, rather sparsely, lunately punctate; pygidium subcylindrical, irregularly punctate, punctures cylinndrical; front tibiae bidentate, early impunctate, tarsi moderately flattened laterally. Length 15 mm., width 6 mm.