Pheidole mackayi ^HNS new species

Types Mus. Comp. Zool. Harvard.

Etymology Named after the collector and myrmecologist William P. MacKay.

Diagnosis Similar in various traits to cerina ^HNS, hizemops ^HNS, micon ^HNS, tachirana ^HNS, and tenebra ^HNS, differing as follows. Major: dark brown; in side view, premesonotal profile almost straight until it drops off posteriorly in a nearly vertical face to the metanotum; pronotum in dorsal-oblique view bilobous, and mesonotal convexity subangulate; eyes relatively large; propodeal spines curve backward; postpetiole from above diamond-shaped; posterior half of dorsal head surface smooth with widely scattered foveae. Minor: eye very large, almost circular, set well forward on head; propodeal spines reduced to denticles; occiput narrowed, its margin concave, lacking nuchal collar.

measurements (mm) Holotype major: HW 0.84, HL 0.86, SL 0.52, EL 0.12, PW 0.44.

Paratype minor: HW 0.40, HL 0.44, SL 0.36, EL 0.08, PW 0.24.

Color Major: body dark, almost blackish brown; appendages light brown.

Minor: body and antennae medium brown, legs yellow.

range Known only from the type locality.

Biology The type colony was collected at a bait in a cut and burned-over forest area.

figure Upper: holotype, major. Lower: paratype, minor. MEXICO: 24 km south of Cintalapa, Chiapas (William P. MacKay). Scale bars = 1 mm.