128 THE WONDERS OF INSTINCT 



We will not insist : the method is a poor one, very waste- 

 ful of effort for, at best, a problematical success. 



We ought to interfere as little as possible and obtain 

 a natural closed circuit. Can it be done? Yes. It 

 lies in our power, without the least meddling, to see a 

 procession march along a perfect circular track. I owe 

 this result, which is eminently deserving of our attention, 

 to pure chance. 



On the shelf with the layer of sand in which the nests 

 are planted stand some big palm-vases measuring nearly 

 a yard and a half in circumference at the top. The cater- 

 pillars often scale the sides and climb up to the mold- 

 ing which forms a cornice around the opening. This 

 place suits them for their processions, perhaps because 

 of the absolute firmness of the surface, where there is 

 no fear of landslides, as on the loose, sandy soil below ; 

 and also, perhaps, because of the horizontal position, 

 which is favorable to repose after the fatigue of the 

 ascent. It provides me with a circular track all ready- 

 made. I have nothing to do but wait for an occasion 

 propitious to my plans. This occasion is not long in 

 coming. 



On the 30th of January, 1896, a little before twelve 

 o'clock in the day, I discover a numerous troop making 

 their way up and gradually reaching the popular cornice. 

 Slowly, in single file, the caterpillars climb the great 

 vase, mount the ledge and advance in regular procession, 

 while others are constantly arriving and continuing the 

 series. I wait for the string to close up, that is to say, 

 for the leader, who keeps following the circular mold- 



