On Aquatic Carnivorous Coleoptera or Dytiscide. 467 
knowledge of the sexes of each, so that the tarsi may be compared, is essential 
before a trustworthy conclusion can be arrived at. 
North America, (Canada). 373. 
585. Hydroporus perplexus, n. sp.—Ovalis, sat convexus, tenuiter pubescens, 
niger, vix nitidus, pedibus fusco-rufis, antennis fusco-nigris, basi rufescente ; pro- 
thorace limbo minus fortiter, disco sparsim subtiliter punctato; elytris sat crebre 
et subtiliter punctatis; coxis posterioribus sat crebre et fortiter punctatis; abdomine, 
basi excepto, minus crebre fere obsolete punctato. Long. 4%, lat. 23 m.m. 
The two specimens I have seen appear to be males, they have the front tarsi 
moderately strongly dilated, with the claws simple. 
North America, (California). 372. 
586. Hydroporus rusticus, n. sp—Oblongo-ovalis, evidenter pubescens, nigricans, 
supra vix dilutior, pedibus rufo-fuscis, antennis fuscis basi minus lete rufo: pro- 
thorace limbo minus fortiter, disco omnino sparsim subtiliter, punctato ; elytris sat 
crebre et subtiliter punctatis ; coxis posterioribus crebre fortiter punctatis ; 
abdomine (basi excepto) minus crebre subobsolete punctato. Long. 4, lat. 
23 ™.m. 
This species is very similar to Hydroporus tartaricus, Lec., (H. nigellus, Mann.) 
(No. 597) but is rather larger, and the disc of the thorax is not quite so destitute 
of punctures. 
North America, (Nevada). 371. 
587. Hydroporus tenebrosus, Lec., M.C.—Ovalis, minus convexus, evidenter 
pubescens, subtus nigricans supra fusco-niger, pedibus rufescentibus, antennis fuscis 
basi rufo ; prothorace limbo sat fortiter, disco subtiliter punctato ; coxis posterioribus 
fortiter punctatis; abdomine (basi excepto) minus crebre subobsolete punctato. 
Long. 43, lat. 24 m.m. 
Mas, supra sat nitidus, subtiliter sed evidenter punctatus, tarsis anterioribus 
et intermediis bene dilatatis, illis unguiculis muticis. 
Fem., opaca obsoletius punctata. 
This species has the hind coxee more coarsely, but the ventral segments less dis- 
tinctly, punctured than in the preceding species. 
The specimen sent me by Dr. Leconte is rather larger and of paler colour than 
the other individuals I have described, H. sub-pubescens is perhaps also this species; 
TRANS. ROY. DUB. SOC., N.S., VOL. II. 3P 
