The attention of the writer was first called directly to this problem by certain observations made along the White Water River, in southeastern Indiana, at the time of the great flood which swept that section of the country in the spring of 1913 —- generally known as the Dayton Flood. The writer was attempting to make collections of insects in the bottom lands of this small tributary of the Ohio river between the downpours of rain on Monday, March 24, 1913, at the time when that particular stream overflowed its banks. The observation that certain forms of animal life were destroyed outright, and others were forced to flee before the rising water, while still others were carried along on floating driftwood and other debris by which they might be introduced into new regions led to analysis of the influence of such floods upon animal life