Cremastocheilus mentalis

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

Key to Trinodia species
Body and legs dark red, surface opaque; head densely punctate; posterior angles of pronotum flat above, no excavation inside and anterior of posterior pronotal angles; elytra densely covered with oblong punctures, separated by their own widths laterally, overlapping longitudinally, with finely reticulate sculpturing between punctures.

A number of specimens of this species have been seen, by the author, in various collections incorrectly determined as Cremastocheilus planipes Horn. C. mentalis differs from C. planipes by being smaller, reddish rather than piceous, by having the punctuation of the head much more dense, the front much more pilose and the hind angles of the pronotum flat above rather than having the outer edges upturned. The compressed legs, mentum and punctuation of the elytra resemble closely those of Cremastocheilus planipes. (Cazier, 1940)

Distribution
Arizona (Cochise Co., Pima Co., Santa Cruz Co., Pinal Co.)

Habitat
Common host is Novomessor albisetosus.

Nomenclature
Holotype female at Arizona State University, collected by Mr. E.R. Leach at Nogales, Arizona, Sept. 6, 1928.

Description
Medium sized; dark, opaque red, rather densely clothed with long brown pile; legs strongly compressed laterally. Head with vertex and front cribrately punctate, punctures shallow; frontal carinae prominent and extending to reflexed clypeus, densely clothed with long brown pile, two small apical tommentose patches, one on each side; clypeus as wide as head, sides of reflexed front margin serrate, clothed with long brown pile; mentum cupuliform, subcylindrical, posterior reflexed margin abruptly elevated posterior to lateral obtuse angles, median portion prominent, acutely angulate and abruptly elevated. Pronotum trilobed, widest at apical third, sides obtusely rounded to apex and base, not greatly constricted, edges shallowly serrate, apical angles auriculate, basal angles projecting posteriorly, impunctate, shining; surface opaque, except for hind angles, lateral lobes cribrately punctate, middle with irregularly placed rather dense pile and shallow, circular punctures. Elytra with sides subparallel, disk shallowly concave, densely covered with oblong punctures, separated by about their own widths laterally, coalescent or overlapping longitudinally, each puncture fiving rise to a long brown hair; meso-episternum inconspicuous above. Beneath rather densely covered with shallow ring-like punctures and brown pile; all femora and tibiae greatly compressed laterally, moderately clothed with brown pile, anterior tibiae bidentate, middle and hind tibiae with subapical acute spine on outer edge, tarsi five-segmented, flattened laterally; pygidium subcylindrical, median line faint, surface densely punctate and pilose dorsally, becoming sparse ventrally, ventral tip shining. Length 12 mm., width 5 mm.