292 THE CANADIAN F.NTOMOLOGIST 



After an interesting chapter on the history and development 

 of tiiis science, the authors discuss the physical .-and chemical 

 properties of water, and of natural bodies of water, regarded as 

 aquatic environments, and also the interrelations of land and 

 water. This is followed by a general account of the various types 

 of aquatic environments, under the sub-headings: "Lakes and 

 Ponds," "Streams," and "Marshes, Swamps -and Bogs." 



The fourth and longest chapter deals with types of aquatic 

 organisms, these being descril)e(l briefl) in untechnical language, 

 particular attention being given to their mode of life and such 

 features of form and structure as indicate their fitness for their 

 particular en\ironnient . 



This and the two f(jllowing chapters, entitled "Adjustment to 

 Conditions of Aquatic Life" and "Aquatic Societies," contain 

 much entomological matter. The latter two chapters are of excep- 

 tional interest to the biologist, and it is doubtful if there is any- 

 where to be found a more admirable analysis of the ecological 

 relations of fresh-water organisms. 



In the concluding chapter. "Inhuul Water Culture," the sub- 

 ject is discussed fnym the economic standpoint, and the possibilities 

 of utilizing the extensive areas of swamp and marsh in North 

 America for intensive fish-culture are clearly demonstrated. Nor 

 are the aesthetic and educational aspects of the subject forgotten, 

 and the authors show their breadth of view in this connection 

 in advocating the preserxation of wet lands in part as sanctuaries 

 for wild life. 



Throughout the book it is the ecological point of view that 

 is emphasized rather than the systematic and morphological, and 

 from this standpoint there is much that is of great interest to 

 students of all groups of aquatic insects. 



The illustrations are numerous and attractive, many of them 

 being reproductions of original photographs and photomicrographs. 

 The chief defect is the somewhat large number of typographical 

 errors, which will doubtless be corrected in a future edition. 



Mailed August 1.5, 1916 



