440 _ BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
in front, with nearly straight sides, concave occipital border and 
narrowly rounded corners; anterior corners right-angled. Vertex 
slightly rounded above, a little longer than the front. Front sepa- 
rated from vertex by a distinct angle, and forming with the mandibles 
a disc; very strongly impressed with a deeper, longitudinal groove at 
middle. Frontal area small, triangular, more deeply impressed than 
the front. Clypeus deeply impressed at middle; the anterior margin 
carinate at middle, broadly crenulate. Frontal carinae strong, 
extending sinuately to ends of antennal scapes. Mandibles very 
short and. thick, the blade slightly concave, edentate. Antennae 
short, the scape extending a little more than half the distance to 
occipital corners, strongly geniculate at the angle which separates 
front from vertex, thickened distally. First funicular joint as long 
as the two succeeding joints, joints 2-8 as long as broad; joints 9-11 
forming a club as long as remainder of funiculus. Eyes large, oval, 
flat, with distinct ommatidia; situated at sides in front of middle. 
Antennal fossae deep; extending to apex of scape. Ocelli distinct, 
the median much the largest, each situated in a foveole, the median of 
which is extended forward asa groove. Thorax rather flat above, sides 
rounded; mesothorax a little longer than broad; scutellum rounded 
behind. Epinotum with subequal base and declivity; the base strongly 
concave at middle, with elevated sides, which terminate in short thick, 
acuminate spines; surface of declivity concave, but less so than the 
base. Petiole elongate; the node transverse, in profile narrowed 
above, constricted behind. Postpetiole twice as broad as petiole, the 
sides produced into angles, rounded in front, constricted behind; in 
profile evenly convex above. Gaster,oval, broad at apex. 
Shining, with abundant silky pilosity, which is partly reeumbent on 
gaster and erect on the other parts of body. Cheeks, front, and 
clypeus devoid of hairs. Vertex longitudinally, crenulately striolate, 
front and clypeus with striolae arranged in a concentric pattern. 
Mandibles with five transverse, diagonal carinae. Thorax, petiole, 
and postpetiole minutely punctate; postpetiole above with five short 
longitudinal carinae. 
Color testaceous; mandibular blades and posterior margins of gas- 
tric segments darker. Pilosity yellow. 
Described from a single female taken at Madeira-Mamoré Camp 
No. 41. It was beneath a log, in company with a colony of Myrmico- 
crypta foreli. This isthe first known South American Pheidole 
belonging to the group of species which have the front of the head 
depressed and disc-like, somewhat similar to that of the major 
worker in Camponotus subgenus Colobopsis. 
