ENGINEERING METHODS 



evening visit. Here and there were scattered over 

 the surface small, irregular heaps of dry leaves, bits of 

 leaves, chips, and broken twigs, which seemed mere 

 accidental drifts and piles (Fig. 41). 



Returning about nightfall, I found the scene wholly 

 changed. Hosts of ants of various sizes were already 



Fig. 41 A CLOSED GATE OF CUTTING ANTS OF TEXAS 



hurrying out of open gates into the neighboring jungle, 

 and two long double columns were stretched from the 

 bottom to the top of the overhanging tree. The ants 

 in the descending columns carried above their heads 

 portions of green leaves that waved to and fro, and 

 glanced in our lanterns' light, giving them a weird 

 seeming as they moved along. It is this habit that has 

 given the insect the popular name of "parasol ant." 



I first directed special attention to the opening and 

 closing of the gates, which occurs before and after every 

 exit. The opening began about dusk. First appeared 

 from beneath the heaps of dry leaves and chippage 

 scattered irregularly over the surface a number of 

 minims, very tiny fellows indeed. They carried from 

 within small grains of soil. Perhaps an interior cave 

 may have been used as a dumping receptacle for the 

 earth-pellets and smaller rubbish. This was a tedious 



process, and little seemed to be accomplished until this 



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