420 bulletin: museum of comparative zoology. 



up some of the individuals, those nearest would turn about and run 

 back, zig-zagging from one ant to another, apparently missing none. 

 An instantaneous antennal communication took place, the warned ant 

 turned also, and almost instantly the whole army was retracing its 

 steps as rapidly as it had come. In a few moments some few would 

 return and then more and in a short time the army would resume its 

 march. At other times a new path was followed. This antennal 

 communication and quick change of direction was observed also in 

 E. pilosum, E. crassicorne, and E. burchelli. 



49. Eciton {Eciton) lucanoides Emery. 



Columns were found at Madeira-Mamore Camps 39 and 41. 



This species was originally described from Peru. The mandibles 

 are armed with a strong spine on the inner side, a little in front of the 

 middle. I am unable to distinguish the minors and mediae of E. 

 lucanoides from those of E. hamatum by any single character. 



50. Eciton (Eciton) burchelli (Westwood). 



This species was moderately abundant on the Rio Madeira, where it 

 was encountered several times at Abuna and at Camp 41, Madeira- 

 Mamore R. R. 



It is rather more aggressive than the other species. When dis- 

 turbed it attacks the intruder very fiercely and persistently. The 

 pain produced by the sting is severe, but of short duration. 



51. Eciton {Eciton) rapax F. Smith. 



Two small files of this beautiful species were found at Porto Velho 

 and Camp 41, Madeira-Mamore R. R. These were running along 

 beneath the loose covering of leaves on the ground. 



The ants were very timid and the file dispersed as soon as it was 

 disturbed. 



52. Eciton {Eciton) rogeri Dalla Torre. 

 Several colonies were taken at Camp 39, Madeira-Mamore R. R. 



53. Eciton {Eciton) vagans (Olivier). 



Found at Independencia and Baixa Verde, where files were fre- 

 quently seen toward evening. 



