472 On Aquatic Carnivorous Coleoplera or Di/tiscidce. 



medio sublaBvi ; eljtris sat crubre et fortiter puiictatis ; coxis posterioribus sat 

 crebix' jjunctatis. Long. 83, lat. Ig m.m. 



The male has the front tarsi a little broader than the female. Tliis form is 

 rather larger and broader than Dytiscus tristis, and has the elytral punctuation and 

 pubescence rather stronger, but I think it will scarcely prove to be a distinct 

 species. 



Eiiio]ie. (Sweden ; Finland ; Germany ; Fi-ance, the Somme, Bedel). 355. 



602. Dytiscus tristis, Payk., Ihjdroporus tristis, 21. C. — Oblongus, parcius 

 pubescens, sat nitidus, nigricans, antennarum basi pedibusque rufis, elytris capiteque 

 fusco-rufis, hoc anterius dilutiore ; prothorace basi fortiter punctate, medio subltevi, 

 elytris sat subtiliter j^arcius punctatis ; coxis sat crebre, fortiter punctatis. Long. 

 3, lat. Ih m.m. 



The sexes in this species are scarcely distinguishable, the male having the tarsi 

 only very little broader than in the female. 



It is doubtful whether Hydroporus varians, Lee, be distinct from this species or 

 not. My two specimens from Massachusetts are rather less elongate, still less 

 pubescent, and rather more strongly punctured above, but with the hind coxse 

 rather less punctured. Hydroporus ruficapillus, Mann., from Sitkha, can scarcely be 

 considered more than a variety of Dytiscus tristis, Payk. ; it is slightly more 

 elongate, has the surface dull, and the pubescence still less. 



Northern Europe ; Siberia ; North America. (Sweden ; Finland, 69'' north, Salilberg ; Scotland ; 

 liasin of the Seme ; Alsatia; Germany). 351. 



603. Hydroporus neglectus, Schaum, M.C. — Oblongus, angustulus, minus pubes- 

 cens, vix nitidus, subtus nigricans, capite anterius rufo, elytris fusco-rufis, prothorace 

 fusco, hoc elytris angustioro, medio parcissime punctato ; elytris sparsim subtiliter 

 punctatis ; antennis gracilibus fusco-rufis, basi dilutiore ; coxis posterioribus sparsim 

 sat fortiter punctatis ; tarsoruni anticorum articulo 3° elongato. Long. 2-;, lat. 

 li m.m, 



Mas, tarsis anterioribus et intermediis latioribus, illis unguiculis insequalibus 

 anteriore crassiore, apice fisso. 



Northern and Central Europe. (Sweden, Finland, England, basin of the Seine, Germany). 353. 



604. Hydroporus scalesianus, Steph., M.C. — Oblongo-ovalis, parcissime jDubescens, 

 nitidulus, feiTugineus, elj'tris plus miiiusve fuscescentibus, abdomine pectoreque 

 nigricantibus ; prothorace medio impunctato ; elytris parcius vix fortiter punctatis ; 

 coxis posterioribus punctis paucis magnis; tarsorum anticorum articulo 3° elongato. 

 Long. 2, lat. 1 m.m. 



