118 ANIilAL INTELLIGENCE. 



parent confusion is that scarcely a single Hypoclinea gets away 

 with a pupa or larva. I never saw the Ecitons injure the 

 Hypoclineas themselves, they were always contented with de- 

 spoiling them of their young. 



The columns of this species ' are composed almost 

 entirely of workers of different sizes ; ' but, as in the 

 species previously mentioned, 'at intervals of two or 

 three yards there are larger and lighter coloured indi- 

 viduals that often stop, and sometimes run a little back- 

 ward, stopping and touching some of the ants with their 

 antennae,' and looking 'like officers giving orders and di- 

 recting the march of the column.' 



Concerning the other habits of this species, the same 

 author writes : 



The eyes in the Ecitons are very small, in some of the 

 species imperfect, and in others entirely absent ; in this they,, 

 differ greatly from the Pseudomyrma ants, which hunt singly 

 and which have the eyes greatly developed. The imperfection 

 of eyesight in the Ecitons is an advantage to the community, 

 and to their particular mode of hunting. It keeps them to- 

 gether, and prevents individual ants from starting off alone 

 after objects that, if their eyesight was better, they might dis- 

 cover at a distance ; the Ecitons and most other ants follow 

 each other by scent, and, I believe, they can communicate the 

 presence of danger, of booty, or other intelligence, to a distance 

 by the different intensity or qualities of the odours given off. I 

 one day saw a column of Eciton hamata running along the foot 

 of a nearly perpendicular tramway cutting, the side of which 

 was about six feet high. At one point I noticed a sort of 

 assembly of about a dozen individuals that appeared in consul- 

 tation. Suddenly one ant left the conclave, and ran with great 

 speed up the perpendicular face of the cutting without stopping. 

 It was followed by others, which, however, did not keep straight 

 on like the first, but ran a short way, then returned, then again 

 followed a little further than the first time. They were evi- 

 dently scenting the trail of the pioneer, and making it per- 

 manently recognisable. These ants followed the exact line 

 taken by the first one, although it was far out of sight. Wher- 

 ever it had made a slight detour they did so likewise. I scraped 

 with my knife a small portion of the clay on the trail, and the 

 ants were completely at fault for a time which way to go. 

 Those ascending and those descending stopped at the scraped 



