406 bulletin: museum of comparative zoology. 



Workers are often seen moving slowly about or remaining motion- 

 less on the stems and leaves of trees and shrubs. The species is 

 partly nocturnal in habit and often enters houses and hunts about for 

 other insects that come to the lights. A nest which I dug out was in 

 the ground among the roots of a plant, about twelve inches below^ the 

 surface. 



13. Edatonima {Eciatomma) confine Mayr. 

 Plate 1, fig. 8. 



A single worker (Plate 1, fig. 8), which agrees well with Mayr's 

 description, was taken at Porto Velho. Apparently the species has 

 not been recorded since Mayr described it from a Colombian specimen. 



The structure of the pronotum is very characteristic. The middle 

 tubercle is prolonged and flattened above, and laterally compressed 

 in front of the pleural spines so that it has the form of a short, thick 

 carina. The lateral spines on the pronotum are short, flattened, and 

 triangular; the epinotal spines are prominent. The sculpture of the 

 head is coarse, that of the rest of the body delicate. The head, 

 thorax, and abdomen are sparsely beset with coarse, erect hairs. 



14. Ectatomma (Gnaviptogenys) concinnum (F. Smith). 



Plate 1, fig. 7. 



Workers (Plate 1, fig. 7) were found at Porto Velho, Abuna, and 

 Madeira-Mamore Camp 39. 



15. Ectatomma (Gnamptogenys) tortuolosum F. Smith. 

 Plate 1, fig. 6. 



Worker. (Plate 1, fig. 6.) Length 7 mm. 



Head, excluding mandibles, a little longer than broad, with slightly 

 convex sides, narrowly rounded posterior corners and concave border. 

 Clypeus nearly as long as broad, the surface depressed; anterior 

 border straight. Mandibles slender, the blade edentate. Antennae 

 robust; scape thickened apically, extending one fourth its length 

 beyond the occipital corners; funicular joints 1 to 3 elongate, sub- 

 equal; joints 3-6 globose, a little longer than broad. Eyes moder- 

 atel}' large, convex, situated at middle of sides of head. Thorax 



