LAKE BLUFF, RAVINE, AND RIVER VALLEY 271 



The river bottom or the 

 flood plain association is a very 

 constant one. It is bordered 

 by a succession of zones on its 

 river side. First there is a 

 zone of bare sand or gravel 

 which is so often inundated 

 that no plants — unless it be 

 an occasional hardy annual 

 weed — grow upon it. Here 

 the toad bug (Fig. 410) is often 

 found, the hooded grouse 

 locust (Fig. 411), some of the 

 same predatory ground beetles 

 found along the lake shore, 

 and the spotted (Fig. 412) and 

 solitary sandpipers. All these 

 feed on small animals washed 

 ashore by the current. This 

 zone, without plant life, may be 

 designated, on its animal side, 

 the spotted sandpiper zone. 



Next comes a zone of low 

 rich soil, inundated in the 

 spring but which later dries 

 out enough so it is populated 

 by such weeds as ragweed and 

 wild sunflower. The granu- 

 lated grouse locust (Fig. 216) 

 is found here early. Later 

 the meadow grasshopper, 

 Xiphidium brevipenne, ap- 

 pears. The long-bodied 

 spider, Tetragnatha lahoriosa 

 (Fig. 413), finds this a 



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1 



Fig. 414. — Kentucky coffee tree 



