March, 1913-] SliERMAN : HaBITS OF THE DyTISCID.E. 51 



peaceful brooks with clean sandy bottoms, like the one running 

 through the golf course near the Moravian Cemetery on Staten 

 Island. 



Shelford took Hydroponis mcllitiis Lee. in great quantities at 

 South Haven, Mich., " in the sand near the edges of very shallow 

 pools left in a partly dry brook, waiting several minutes for the 

 beetles (which are exactly the color of sand) to crawl out." 



Hydroponis vittatns Lee. was also found by Shelford in abundance 

 in the gravel at Edge Brook, 111., near the shore of the old course of 

 the Chicago River. This gravel was full of filamentous algas. I first 

 saw this beautiful beetle alive at Chester, Minn., in a small sandy 

 pool left in the almost dried up bed of a good sized brook, and a 

 few days afterward I accompanied Professor Shelford's class on one 

 of their memorable picnics to the Edge Brook locality and took a 

 great many more. 



Hydroponis conciituus Lee. {zvickhanii Zaitzev.) I have usually 

 found in brooks where cress was growing, brooks usually with muddier 

 bottoms. 



Hydroponis spiiriiis Lee. lives among the submerged roots of plants 

 living on the banks of deeper and larger brooks. 



Hydroponis solitarius Sharp also lives in the larger brooks or 

 small rivers (Pine River, Lake Superior; Ten Mile River, Wingdale, 

 New York; Black Creek, Esopus, New York). 



Hydroponis septentrionalis Gyll. has been found rather common in 

 recent years by Messrs. Sheriff and Frost at Fabyans, N. H., in the 

 Ammonoosuc River, which is a rapid stream at that point. Mr. 

 Sherrifif says that " it confines itself to the water's edge, hiding under 

 submerged stones." 



Hydroponis cimicoides Sharp and venustiis Lee. are two more 

 species of this genus living in running water. Both of these are 

 abundant in the clean sandy pool and brook flowing therefrom, at the 

 bottom of the lake dam at Lakehurst, N. J. 



Dytiscidae of other genera also occur in running water. 



In the eddies of the eastern branch of the Potomac River at 

 Bladensburg, Md., and also- in the brook running through my uncle's 

 farm at Ash Grove, Va., are found the beautiful Laccophillus described 

 in manuscript as ScJnvarsi by Mr. Roberts and also the fine unde- 

 scribed Hydroponis to which I propose to give Zimmermann's mss. 

 name of dilatatus. 



