March, I9I3.] LenG : AqUATIC COLEOPTERA. 37 



little animals that feed upon leaves; so also with Copelatns glyphicus 

 which I have found only in submerged rotting cattails, between the 

 layers of which their greatly flatteried bodies permit them to crawl. 

 Such species might be called rare, it is really only necessary to find 

 their environment to find them in sufficient numbers. On the other 

 hand, a genus like Ilybiits seems to turn up in a variety of situations. 

 As one recalls the days spent with the water net, how it comes to mind 

 that Linell told us the larger species preferred the deeper waters, 

 and must be hunted by wading bare-legged into the pond, a method 

 that Mr. Roberts' hip boots, carried in a neat suitcase, seemed to in- 

 dorse but improve. How one thinks longingly of the day Canthydrus 

 puncticollis was fished out of a tiny spring hole on Staten Island, but 

 only one specimen not since repeated ; and of another day when 

 dragging the net along the grassy edge of a little brook, produced a 

 few Deronectcs depresses. Along the edge of the Staten Island 

 salt meadow, I have found Coclambus impressopunctatus with scarcely 

 enough water to keep them as wet as were my feet. It may be that 

 some of the associations of environment and species are deceiving on 

 account of the facility with which at least some species fly by night, 

 especially during their mating season, and of the lack of discrimina- 

 tion they display in alighting. I have heard of their mistaking green- 

 house glass for water, and if capable of so serious an error, they 

 might easily get mixed as to their appropriate environments, therefore 

 too much importance must not be attached to records of the finding of 

 a few imagos. Nevertheless it is evident that for most species of 

 water beetles a particular environment is an absolutely essential requi- 

 site for successful search. 



The -Hydrophilidse are generally regarded as vegetable feeders, 

 though Folsom says the larvae are at time carnivorous, and Miss 

 Bamford found them in captivity practically omnivorous. As now 

 classified in our books we have three sub-families of vastly different 

 habits combined under the name, namely : Cercyon and its allies, found 

 in manure and in no sense aquatic, the Helophorini found on plants 

 beneath the surface, crawling on them and incapable of swimming, 

 resembling rather the Elmidse in their habits, and the true Hydro- 

 philns and its allies, all more or less free swimming creatures 

 though none of them can equal the Dytiscidae in this respect. As 

 would naturally follow from their habits, these feeders upon vegetable 



