388 



ANNUAL REPORT SMITHSONIAN INSTITUTION, 1955 



For an Eciton hurchelU raid nearing the height of its development 

 in swarming, picture a rectangular body of 15 meters or more in width 

 and 1 to 2 meters in depth, made up of many tens of thousands of 

 scurrying reddish-black individuals, which as a mass manages to 

 move broadside ahead in a fairly direct path. When it starts to 

 develop at dawn, the foray at first has no particular direction, but in 

 the course of time one section acquires a direction through a more 



I 





Figure 2. — Diagram of an Eciton burchelli nomadic-phase raid at 11 a. m., after about five 

 hours of raiding. 1, Swarm (now approximately 70 meters from the bivouac and about 

 15 meters wide); Ps, pseudopodic advance column; 2, fan-shaped mass of consolidation 

 columns; 3, principal column (the alternative column disappeared within the following 

 hour); 4, the bivouac, within a hollow log; 5, remains of large fallen tree, a spot thoroughly 

 raided by the swarm about 2 hours previously; 6, a subswarm recently formed by division 

 of the main swarm. 



