INHABITING NORTn AMERICA. 103 



Length more than tliree-twentieths of an inch. 



Dytiscus niger. Mehh. Calal. 



Body black, obscure, very numerous, minute, villous punc- 

 tures, hairs adpresscd to the surface. 



Head obscure rufous, paler beneath, dusky each side of the 

 front, a slightly indiMitrd spot each side before instead of 

 the impressed line and punctures; anterinn' dusky towards 

 the tip of eachof tlie terminal joints; palpi, terminul joints 

 blackish- 



Thorax black, very obscure rufous on each side, doreal line 

 none. 



Elytra black, vciy obscure rufous each side near the base, 

 stri.T or macuhe none ; epiplenra rufous. 



Pectus and pnsfpectus black ; feet rufous ; renter black, seg- 

 ments sliglitly piceous at tip. 



4. H. ^catascopium black, obsolete, spotted and lineated with 

 rufous ; feet rufous. 



Length three-twentieths of an inch. 



Body black, obscure, with villous punctures, hairs adpresscd 

 to the surface. 



Head obscure rufous, dilated orbits and base black, indented 

 frontal spots eacii side instead of impressed lines and [junc- 

 tures ; antenna', terminal joints blackish at their tips ; pafpi 

 terminal joint black. 



Thorax black, a central longitudinal spot, and irregular sub- 

 marginal one each side rufous, dorsal impressed line none. 



Elytra black, margirj rufous, with a transverse irregular pro- 

 cess at base, and another at the middle, and common api- 

 cial band, a double sutural line, an abbreviated line arising 

 from the middle of the l^ase, and a subsutural spot near 

 the middle, rufous, a distinct sutural stria and an obsolete 

 one near the middle. 



Feet rufous. 



5. H. *lacustris rufous, obscure; a common, impressed. Ion- 



