478 On Aquatic Carnworous Coleoptera or Dytiscide. 
prothorace anterius in medio obsolete punctato; coxis posterioribus sparsim sat 
distincte punctatis; abdomine tantum basi utrinque punctato; prosterni processu 
anterius depressiusculo, haud prominulo. Long. 4, lat. 24 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. Hydroporus inornatus, n. sp.—Ovalis, sat convexus, evidenter pubescens, 
crebre subtiliter punctatus, 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. 33, lat. £3 m.m. 
Mas, tarsis anterioribus evidenter dilatatis, unguiculis fere 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), 334. 
622. 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 zqualiter punctato, elytris crebre distincte punctatis ; 
coxis posterioribus sparsim sat distincte punctatis; abdomine sparsim obsolete 
punctato, sed basi utrinque punctis majoribus; prosterni processu angusto, vix 
marginato, sat compresso, anterius depressiusculo et subprominulo. Long. 33, 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 latus, evidenter 
pubescens, 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 haud compresso, versus apicem carinato. Long. 44, lat. 23 m.m. 
Mas, 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 prosternal process flatter, and the male tarsi not 
quite so broad. I do not know the female. 
North America. 331. 
