FOREWORD. 



It has been the aim of the writer to gather together, within 

 the covers of one volume, the gist of all the information now 

 available concerning the biology of the aquatic Hemiptera. 



There was no intention in the beginning to include descrip- 

 tions of species or other taxonomic matter. It was found, 

 however, that there exists no work containing the descriptions 

 of American genera and species.* These have been gathered 

 together from various sources, some of them well nigh inac- 

 cessible, and are included in this paper to facilitate further 

 study in the group. 



The writer does not pretend to be an authority on systematic 

 literature. He has followed Van Duzee's checklist and cata- 

 logue faithfully, digressing only in those cases where he has 

 had the advice from taxonomists in the various families. Keys 

 have been improvised from the literature, reduced to a synop- 

 tic plan, and tested upon all available material. This phase 

 of the work, however, has been secondary and incidental to 

 the main problem of extending the range of our knowledge of 

 the ecology and biology of the water bugs. To this end the 

 writer has searched the early literature for the first biological 

 notes applied to the water bugs, has gleaned the periodicals, 

 other serials and texts, and arranged the results in this paper 

 under the families and genera as they now stand, adding his 

 own contributions on the behavior, life history and ecological 

 relations of these most interesting insects. 



* Generic descriptions are often brief notes and specific descriptions are omitted for 

 Belostomatidse and Corixidfe, groups now undergoing careful revision. 



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