542 



Saw-flies, Gall-flies, Ichneumons, 



from the neighboring grasses, and their well-marked runways make dis- 

 tinct paths through the dense grass surrounding the nest. Immediately 



FIG. 746. Mound-nest of the western agricultural ant, Pogonomyrmex occidentalis. 

 (After photograph by G. A. Dean, Wallace, Kans.) 



around the nest this grass is cleanly cut away. The widespread popular 

 belief that these ants plant or sow (with purpose or intention) the seeds of a 



FIG. 747. Vertical section of mound-nest of the western agricultural ant, Pogonomyrmex 

 occidentalis; this nest about 5 feet deep by 6 feet in diameter. (After photograph 

 by G. A. Dean, Wallace, Kans.) 



favorite grass, Aristida, is shown by Wheeler to be untrue; what does often 

 happen is that the carrying out of the chaff and sometimes sprouted seeds 



' 



