1914] W heeler—Harvesting Ants 151 
Described from a large number of workers and a single female, 
which I took December 12-14, 1911, from many nests at Zacapa, 
Guatemala, in the extremely arid plains known as “La Fragua,” a 
region with pronounced xerophytic vegetation (giant cacti, etc). 
The ants were nesting in the fields, the grass of which, at the time 
of my visit, was parched and had been eaten down to the rects by 
the cattle. The nests were regular, flattened craters from 2-8 
inches in diameter, not surrounded by clearings, and much like 
the nests of the other small North American species of Pogonomyr- 
mex. <A pile of grass-seed or chaff, often found to one side of the 
crater, showed that the species is granivorous like other members 
of the genus. Many nests were also found in the sand-ballast of 
the railroad near the town of Zacapa. The worker is readily dis- 
tinguished from that of most of the described species of Pogono- 
myrmex by the peculiar shape of the thorax, clypeus and petiole 
and by the 5-toothed mandibles. 
2. Pogonomyrmex huachucanus sp. nov. 
Worker. Length 4.5-5 mm. 
Head subrectangular, excluding the mandibles as broad as long, with nearly 
straight lateral and feebly excised posterior margin. Eyes elliptical, rather convex, 
at the middle of the sides of the head. Mandibles with convex external and rather 
oblique apical borders, the latter 6-toothed. Clypeus moderately convex, its ante- 
rior border marginate, distinctly bidentate and arcuately excised between the teeth. 
Frontal area distinct, with median carinula. Antenne not reaching halfway be- 
tween the eyes and the posterior corners of the head; first and second funicular 
joints distinctly longer than broad, remaining joints, except the last, as long as 
broad. Thorax slightly longer than the head without the mandibles, from above 
broadest through the pronotum, but with the transverse diameters of the meso- 
and epinotum equal; in profile the dorsal outline is convex in the pronotal region 
but the mesonotum and base of the epinotum form a straight line gently sloping to 
the two spines, which are shorter than the base of the epinotum, rather slender 
but blunt, closely approximated at their bases and directed upward, outward and 
slightly backward. The epinotal declivity is short, abrupt and much as in P. guate- 
maltecus, forming in profile a right angle with the metasternal angles, which are 
in turn rectangular. Petiole with slender, laterally much compressed peduncle, 
half as long as the node and with a distinct but rather blunt anteroventral tooth. 
Node from aboye subelliptical, pointed or acuminate in front, less than twice as 
long as broad, its posterior surface rather sharply marked off from the anterior, so 
that the summit appears pointed also in profile. The anterior surface is slightly 
convex in profile and rises abruptly and perpendicularly from the peduncle, the 
posterior surface, also slightly convex, is about one and one half times as long as 
the anterior and constricted near its posterior end. Postpetiole from above sub- 
