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. xVntennae 

 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 as a 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 recumbent 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-Mamore Camp 

 No. 41. It was beneath a log, in company with a colony of Myrmico- 

 crypta foreli. This is the first known South American Pheidole 

 belonging to the group of species which have the front of the head 

 depressed and disc-likcj somewhat similar to that of the major 

 worker in Camponotus subgenus Colobopsis. 



