478 On Aquatic Carnivorous Coleoptera or Dytiscidce. 



prothorace anterius in medio obsolete punctato ; coxis posterioribus sparsim sat 

 distincte punctatis ; abdomine tantum basi utrinque punctato ; prosterni processu 

 anterius dejjressiusculo, baud promiuulo. Long. 4, lat. 2i m.m. 



The male seems to differ from the female only by the moderately dilated front 

 tarsi ; the sculpture of the thorax in this species is more diminished than in its 

 close allies. 



North America, ^Detroit, Michigan). 335. 



621. Bydropox'us inornatus, n. sp. — Ovalis, sat convexus, evidenter pubescens, 

 crebre subtiliter jjunctatus, subtus nigricans, supra fusco-niger, limbo dilutiore, 

 pedibus rufis, antennis fuscis, basi rufo ; coxis posterioribus sparsim sat distincte 

 punctatis ; abdomine crebre, evidenter punctato ; prosterni processu angustulo, 

 anterius depressiusculo et subprominulo. Long. S§, lat. Li m.m. 



Mas, tarsis anterioribus evidenter dilatatis, unguiculis {ere simplicibus. 



This species has the ventral segments much more distinctly punctured than has 

 the following species, (Hydroporus niger). I do not know the female. 



North America, (Massachusetts). 33-t. 



G22. Hydroporus niger, Say, M.C. — Ovalis, sat convexus, minus elongatus evi- 

 denter pubescens, subtus nigricans, supra fusco-rufus, pedibus rufis, antennis fuscis, 

 basi rufo ; thorace subtiliter sequaliter punctato, elytris crebre distincte punctatis ; 

 coxis posterioribus sparsim sat distincte punctatis ; abdomine sparsim obsolete 

 punctato, sed basi utrinque punctis majoribus; prosterni processu angusto, vis 

 marginato, sat compresso, anterius depressiusculo et subprominulo. Long. Ss, lat. 

 2 m.m. 



Mas, tarsis anterioribus fortiter dilatatis, unguiculis fere simplicibus. 



I do not know the female of this species. 



North America, (Massachusetts). 333.' 



623. Hydroporus latifrons, n. sp. — Oblongo-ovalis, minus la'.us, evidenter 

 l)ubescens, subtiliter punctatus, nigricans, pedibus rufis, capite, thoracis elytro- 

 rumque lateribus rufescentibus, antennis rufo-fuscis basi rufo ; subtus nitidus, coxis 

 posterioribus obsolete punctatis, abdomine tantum basi utrinque punctato; pro- 

 sterni processu baud compresso, versus apicem carinato. Long. 4i, lat. 2s m.m. 



3Tas, tarsis anterioribus et intermediis bene dilatatis. 



Rather narrower than H. modestus (No. 627), with the punctuation of the upper 

 surface a little more distinct, the prostornal process flatter, and the male tarsi not 

 quite so broad. I do not know the female. 



North America. 331. 



