332 WILLIAM MORTON BARROWS. 



EXPLANATION OF PLATE III. 



FIG. 5. A photograph showing the spider in the normal resting position in the 

 web, while the vibrator is in motion. The arrow indicates the place where the 

 vibrator straw touches a radial strand. The doubling or blurring of the lines of the 

 web shows the distribution of the vibrations. 





