FOREWORD 



Minnows and frogs and brown water beetles, scurrying to 

 cover as we approach the shore of a still clear pond, show us 

 that the water has some very lively inhabitants. They swim 

 and dive and paddle in the open until we come, and then they 

 hide from us distrustfully. Theirs is another world than ours. 

 In that world there are strange living creatures in endless 

 variety. There are big and little, swift and slow, strong and 

 weak, graceful and ungainly: all are bom to feed and grow and 

 reproduce, to hunt and be hunted, to strive for a livelihood; 

 and in so doing to fill a place in the household of nature-. 



No one who has lived by clear waters can have failed to see 

 something of their wonderful life: minnows on the shoals; 

 caddis worms dragging their cumbersome portable houses over 

 the brook bed ; the young of mayflies clinging to the stones in 

 the riffle, or the adult mayflies in their dancing nuptial flight in 

 the air above the stream; and what could be more interesting? 



To make the knowledge of the whole range of life in ponds 

 and streams a little more easy of access is a major purpose of 

 this book. And with that knowledge will come appreciation, 

 and a purpose to aid in keeping the waters free from pollution. 

 Clean waters are always charming ; and nothing is more sordid 

 and unwholesome than polluted water. Here is a public ser- 

 vice of no small moment. It is all in the interest of a better 

 human environment; better for health, for recreation, for 

 instruction, and for aesthetic pleasures. 



A book like this cannot fail to render good service since it 

 tells the simple truth about aquatic creatures in an interesting 



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