2 University of Michigan 



imum width, and here there are considerable areas of sand, 

 exposed to strong wind and wave action, and a sparse vegeta- 

 tion. On the east and north shores there are several beach 

 pools in various stages of formation, from which some of the 

 best collections of Hemiptera were made. The region about 

 Douglas Lake is very sandy, and there are no extensive marsh 

 areas in the vicinity; the plant associations developed on low 

 moist ground are of the cedar-sphagnum bog type. 



In the present article an attempt has been made to list as 

 completely as possible the aquatic Hemiptera found in this 

 part of Michigan. The hemipterous fauna of the state has as 

 yet been studied only incidentally, in connection with other 

 problems, and published records for the various species are 

 very few indeed. This report is based on collections made by 

 Miss Eva G. Miller in 1913, by Miss Miller and others in 

 1914, and by Miss Priscilla Butler and myself in 1918. Use 

 has also been made of an unpublished manuscript by Miss 

 Miller on her collection of 1913. The field work was done 

 under the direction of Professor Paul S. Welch, in the months 

 of July and August, during the regular session of the Uni- 

 versity of Michigan Biological Station, which is located on 

 Douglas Lake. 



The species found here were for the most part determined 

 by the writer. Special acknowledgments are due to Professor 

 J. F. Abbott for determination of several species of the Corix- 

 idae, and to ]Mr. J. R. de la Torre-Bueno for identification of 

 several of the other forms, as well as for verification of the 

 determinations of the writer. 



Field Stations 

 In order to facilitate collection, and for convenience in 

 keeping records, twelve stations were selected for field work, 

 in 191 3, which included the different habitat types found in the 



