152 Psyche [October 
globular, a little broader behind than in front, a little broader than long and some- 
what broader than the petiolar node. In profile the dorsal surface is very Convexs 
the ventral bears a rounded boss in its middle. Gaster elliptical, proportionally 
larger than in P. guatemaltecus 
Mandibles, gaster and legs shining, remainder of body appearing more subopaque, 
owing to their sculpture. Mandibles longitudinally striated; clypeus and head 
longitudinally rugose, the rugze being moderately strong and numerous and dis- 
tinctly and gradually diverging from the median line towards the posterior corners; 
the interrugal spaces densely punctate. Thorax throughout reticulately rugose, 
the rugze being somewhat coarser and further apart than on the head, longitudinal 
on the pronotum and pleurz and arcuately transverse on the mesonotum and base 
of the epinotum. Peduncle and anterior surface of petiolar node shining, finely 
shagreened, posterior surface coarsely and irregularly rugose and punctate. _ Post- 
petiole finely and densely punctate. Gaster very smooth and shining even at the 
base, with minute and sparse piligerous punctures. Legs finely shagreened and 
sparsely punctate, antennal scapes longitudinally rugulose. 
Hairs pale yellow, erect, of unequal length, covering all parts of the body, longest 
on the dorsal surface. Ammocheetz well-developed on the clypeus, ventral sur- 
faces of mandibles and gula, but the psammophore is restricted as in P. guatemalte- 
cus and does not extend to the posterior and lateral borders of the head. 
Deep red, lower surface of head, the legs, coxee and gaster paler and more yellow- 
ish; dorsal surface of first gastric segment with a dark brown cloud on each side 
and usually with a median longitudinal streak of the same color. Mandibular 
teeth and anterior border of clypeus black. 
Described from twenty-two specimens taken by myself Novem- 
ber 11, 1910, from a single nest on the rocky southern wall of Miller 
Canyon in the Huachuca Mountains, Arizona, at an altitude of 
about 5,600 feet. This nest was under a small, flat stone and 
resembled the nests of P. (Ephebomyrmex) imberbiculus Wheeler, 
which I have seen in the mountains of Texas. 
At first sight P. hwachucanus resembles guatemaltecus, but closer 
comparison reveals many differences, especially in the shape of 
the thorax and petiole, not the least being the presence of epinotal 
spines in the former species. This is, indeed, unlike any of the 
known North American species but singularly close to P. bispino- 
sus Spinola of Chili, as I find by comparison with cotypes of the 
variety semistriatus Emery received from Professor Silvestri. ‘The 
thorax in bispinosus, however, is more flattened dorsally in front 
than in huachucanus, the metasternal angles are rounder, the petio- 
lar node is lower and the postpetiole is as long as broad and less 
globular. The gaster of the typical bispinosus is said to be smooth 
and shining as in huachucanus, but in the variety semistriatus tts 
