Formicoxenus hirticornis

Nests in the colonies of Formica obscuripes and possibly Formica integroides.

Identification
The eyes have several erect hairs and the dypeus of the worker is weakly depressed in the middle near the anterior border of the dypeus, and is without a medial carina, although several poorly developed lateral carinae are present. The propodeal spines are well developed, and thickened throughout. The anterior face of the petiole meets the dorsum in an angle, the posterior face is convex and rounded. The dorsum of the postpetiole is completely covered with punctures. The mesosoma has dense punctures. (Mackay and Mackay 2002)

Distribution
North and South Dakota, south to Colorado, west to California.

Distribution based on Regional Taxon Lists
Nearctic Region: Alberta, Canada, Canada, United States.

Habitat
Pine forest

Nomenclature

 *  hirticornis. Leptothorax (Leptothorax) hirticornis Emery, 1895c: 319 (w.) U.S.A. Smith, M.R. 1939c: 176 (q. ergatoid); Snelling, R.R. 1965a: 18 (q.m. ergatoid). Combination in L. (Mychothorax): Emery, 1924d: 262; in Mychothorax: Ruzsky, 1936: 96; in Formicoxenus: Buschinger, 1979a: 61. Senior synonym of formidolosus: Smith, M.R. 1939c: 177. See also: Wheeler, W.M. 1903c: 224; Francoeur, Loiselle & Buschinger, 1985: 382.
 * formidolosus. Leptothorax (Mychothorax) hirticornis var. formidolosus Wheeler, W.M. 1915b: 415 (w.q.) U.S.A. Junior synonym of hirticornis: Smith, M.R. 1939c: 177.