On Aquatic Carnivorous Coleoptera or Dytiscide. 423 
obsoleta ; subtus dense reticulato-punctatus, coxis posterioribus interne punctis 
majoribus conspicuis; prothorace basin versus nullo modo angustato, angulis 
posterioribus rectis ; elytris humeris emarginatis. Long. 43, lat. 23 m.m. 
Ido not see any evident sexual distinction in this species. 
Central and Southern Europe; (Black Forest ; Grande Chartreuse; Alps; Pyrenees; Reynosa ; 
Italy). 304. 
459. Hydroporus platynotus, Germ., M.C.—Subquadrato-ovalis, niger, opacus, 
subtiliter pruinoso-pubescens, antennis pedibusque rufescentibus, dense subtilissime 
punctatus et supra, presertim in elytris, fortiter punctatus; elytris sulca basali 
longitudinali subobsoleta; subtus dense subtiliter reticulato-punctatus, coxis 
posterioribus interne punctis majoribus minus, vel vix, conspicuis ; prothorace basin 
versus haud angustato, sed angulis posterioribus subrotundatis. Long. 4, lat. 
253 m.m. 
The sexual characters are but slight, the male is rather narrower than the female, 
and has the middle joints of the antennze more developed and the thorax a little 
straighter at the sides. 
Central Europe ; (apparently confined to Germany). 303. 
460. Hydroporus bicostatus, Schaum, M.C.—Oblongo-ovalis, nigricans, vel 
rufescens, opacus, subtilissime pruinoso-pubescens, thorace elytrisque fortiter crebre 
punctatis, elytris medio costa longitudinal, elongata, bene elevata, aliaque externa, 
abbreviata, obsoleta; subtus dense subtiliter reticulato-punctatus, coxis posterioribus 
punctis majoribus sparsis sat conspicuis; prothorace basin versus haud vel vix 
angustato, angulis posterioribus haud rotundatis. 
Mas, angustior, nigricans. Long. 44, lat. 2s m.m. 
Fem., latior, rufescens. Long. 5, lat 24 m.m. 
Besides the difference in colour and stature, the male has the thorax not narrowed 
towards the base, and has a minute tubercle on the prosternum, while the female 
is without this tubercle, and has the thorax just a little narrowed from the middle 
to the base. 
Spain and Portugal, but very local; in running streams. 302. 
461. Hydroporus latus, Steph., M.C.—Latiusculus, minus depressus, subopacus, 
ferrugineus, vel fusco-ferrugineus, elytris magis fuscis humeris rufescentibus, 
antennis pedibusque dilute rufis; tenuissime vix perspicue pubescens, corpore 
subtilissime dense punctulato, sed supra punctis majoribus, profundis, numerosis 
conspicuis adsperso. Long 43, lat. 23 m.m. 
In the male the front and middle tarsi are still broader than they are in the 
