416 bulletin: museum of comparative zoology. 



little broader, broadest behind, sides nearly straight; in profile 

 gradually elevated from base to angle of declivity; declivity half as 

 long as the basal part, with the surface flattened. Petiole from 

 above very little broader than long, anterior margin straight, at 

 corners of base with prominent lamellate projections, that appear as 

 spines from above; sides rounded, posterior border feebly rounded; 

 in profile deeper than thick, with nearly straight anterior and posterior 

 surfaces, slightly convex above. Gaster cylindrical, strongly nar- 

 rowed toward apex; the first segment noticeably broader than the 

 second and equal to it in length; a distinct ventral spine present at 

 base. Sting comparatively large. Legs very slender. 



Head, thorax, and petiole subopaque, closely, foveolately punctate 

 throughout; pleurae of pro- and mesothorax and anterior coxa 

 obliquely rugulosely striolate; collar transversely rugulose-striolate. 

 Mandibles shining, finely punctate. Antennae and legs subshining, 

 finely punctate. Gaster shining, minutely punctate. 



Body, legs, antennae, and mandibles with semierect pilosity. 



Head, mandibles, thorax, and petiole fuscous to piceous; borders 

 of the frontal lobes, a round spot on the pronotum, the gaster and 

 legs red. The borders of the gastric segments are infuscated. 



Described from several specimens taken at Camp 39, Madeira- 

 Mamore R. R. The colony was discovered quite accidentally by 

 scratching away some of the leaves and debris with which the ground 

 in the forest is always covered. As far as I could ascertain the ants 

 were traveling in a definite direction. Some of those before me are 

 red in color, evidently immature. Nothing seems to be known re- 

 garding the habits of the species of this interesting genus, specimens 

 of which are rare in collections. The four known species have each 

 been found only once. 



38. Ponera trigona Mayr. 

 One small colony was found at Manaos. 



39. Ponera oyaciceps Mayr. 

 Several colonies were taken at Ceara-Mirim. 



40. Ponera distinguenda Emery. 

 Numerous workers were taken at Camp 39, Madeira-Mamore R. R. 



