450 On Aquatic Carnivorous Coleoptera or Dytiscide. 
564. Hydroporus discretus, Fairm., M.C.—Ovalis, breviusculus, minus convexus, 
subtiliter pubescens, subnitidus, niger, antennis pedibusque rufis, ilis extrorsum 
fuscescentibus ; thorace elytrisque crebre, eequaliter, sat subtiliter punctatis ; coxis 
posterioribus crebre fortiter punctatis. Long. 3, lat. 13 m.m. 
The sexual differences are extremely slight. I find it so difficult to distinguish 
between certain specimens of this and the H. corsicus and H. neuter, that I think 
they may prove all one species. 
Europe, from Scotland to Alsasua, (Cantabrian mountains). 386. 
565. Hydroporus corsicus, Wehncke, Berl. Ent. Zeit. XV, p. 163.—Ovalis, sat 
convexus, subtiliter pubescens, nitidus, niger, antennis pedibusque rufis, lis vix 
fuscescentibus; thorace elytrisque crebre equaliter distincte punctatis; coxis 
posterioribus crebre, fortiter punctatis. Long. 35, lat. 17 m.m. 
This species is very close to Hydroporus neuter, but is rather narrower and 
more oblong, and generally has the punctuation of the elytra rather coarser and 
less close. I see no sexual distinctions. 
Corsica. 385, 
566. Hydroporus neuter, Fairm. Faun. Fr. p. 205.—Ovalis, sat convexus, 
crebrius subtiliter pubescens, nitidus, niger, antennis pedibusque rufis, illis vix 
fuscescentibus ; thorace elytrisque zequaliter, subtiliter fere dense punctatis ; coxis 
posterioribus crebre fortiter punctatis ; abdomine nitido, medio parce subtilissime 
punctato. Long. 33, lat. 17 m.m. 
There seems to be scarcely any difference between the sexes. The species seems 
to be variable, and is very closely allied to H. diseretus (No. 564), but it is usually 
larger and more finely punctured, but some specimens of the two forms approacl 
very closely to one another. 
A specimen sent me by M. Fairmaire, labelled “neuter, Paris,” seems to be a 
variety of this species with the ventral segments in the middle rather more closely 
punctured. 
Europe ; (Pyrenees, Savoy). 384. 
567. Hydroporus fuscipennis, Kies., M.C. —Ovalis, sat convexus, subnitidus, 
crebrius evidenter pubescens, crebre, eequaliter, minus subtiliter punctato, niger, 
pedibus obscure rufis, antennis gracilibus, fuscis basi rufo, capite elytrisque fuscis ; 
coxis posterioribus fortiter, sat crebre punctatis, abdomine evidenter punctulato, 
segmento ultimo distincte punctato ; tarsis anterioribus articulo tertio (preesertim 
in femina) sat elongato. Long. 32, lat. 1s m.m. 
