Cremastocheilus hirsutus

One of about thirty-five species of myrmecophilous Cremastocheilus. The host ant is Pogonomyrmex rugosus, Pogonomyrmex barbatus and Pogonomyrmex maricopa.

Key to Trinodia species
Body dark red, subopaque; anterior tibias pedunculate basally, upper tooth near middle; posterior tibias subpendunculate; mentum slightly cup-shaped; posterior pronotal angles almost perpendicularly inclined; edge of pronotum centrad of posterior angles upturned, forming a deep excavation anteriorly; elytra with dense elongated punctures.

Distribution
Arizona (Cochise, Co., Santa Cruz Co., Yavapai Co.); New Mexico (Hidalgo Co.)

Habitat
Common host is Pogonomyrmex barbatus and Pogonomyrmex maricopa.

Nomenclature
Type, a unique is in the Van Dyke collection at the California Academy of Science. Captured near Prescott, Ariz., Yavapai County, June 11, 1910 by Mr. J. Aug. Kusche and by him kindly presented to Van Dyke.

Description
(from Van Dyke, 1918) Robust, castaneous, subopaque, clothed with yellowish pubescence, long on the elytra and median portion of pronotum, elsewhere moderate in length. Head moderately closely punctured posteriorly, finely and sparsely punctured in front, occipital region transversely depressed, widest across eyes and rapidly narrowing behind them; clypeus viewed from above, rounded at sides and almost transverse in front, with a well-marked carina at middle which, however, does not reach the anterior margin but projects forward free and horn-like, margin widely reflexed and forming an elevated semicircle as seen from in front, fimbriated at sides; submental plate transversely oval, pointed behind, the sides and posterior margin reflexed, the latter quite markedly. Thorax broad, almost as wide as the elytra, narrowed behind, sides arcuate in front, suddenly excavated posteriorly to the posterior angles, which are acute, of moderate length, and project directly backwards, anterior angles with a deep incision forming in front an auriculate lobe, anterior margin deeply semicircularly emarginate, disc trilobed, the median portion some-what depressed, with a longitudinal impression at middle, surface coarsely but shallowly punctured and somewhat subopaque, the lateral portions coarsely and deeply punctured outwardly and smooth toward inner bounding sulci and posterior angles. Elytra with disc flat, sides nearly vertical, discal region with irregular, shallow, elongate, and more or less confluent variolate foveae, surface more or less subopaque. Body beneath coarsely, sparsely punctured on thorax, finely punctured in transverse rows on abdomen, all markedly hairy as above. Legs not unusually dilated, anterior tibia with the upper tooth near the middle and the terminal long and curved, middle and posterior tibia of normal form, rather thick, more slender at base, and with small, acute dentation at middle; tarsi ambulatorial, cylindrical, and at least two thirds length of tibiae. Length 12 mm., breadth 4.5 mm.