On Aquatic Carnivorous Coleoptera or Dytiscide. 475 
Mas, tarsis anterioribus leviter dilatatis unguiculis vix ineequalibus. 
This species differs from H. incognitus by the larger size and more elongate form, 
and by the longer tarsi, as well as by the more distinctly marked elytra, and some 
slight differences of sculpture and pubescence. The sexes, as in H. incognitus, are 
very difficult to distinguish. 
Southern Europe and Algeria, (Pyrenees, Tuscany, Corsica, Algeria). 346. 
611. Hydroporus incognitus, Sharp, Ent. Mo. Mag. VI, p. §4.—Ovalis, sat 
convexus, subnitidus, minus dense pubescens, subtus niger, supra fuscus, capite 
prothoraceque lateribus rufis, illo vertice utrinque fusco, elytris basi vage testaceo, . 
sat evidenter punctatis, pedibus rufis, antennis rufo-fuscis basi rufo; coxis 
posterioribus sparsim punctatis. Long. 35, lat. vix 2 m.m. 
Mas, tarsis anterioribus leviter dilatatis unguiculis vix ineequalibus. 
This species is broader than Dytiscus palustris, has the markings of the elytra 
more indistinct, the surface less opaque, the pubescence more scanty, and the tarsi 
slender, the sexes being only to be discriminated by a very careful examination : 
the prosternal process, likewise, 1s more slender. 
Central Europe, (Britain, Belgium France, Savoy). 345. 
612. Dytiscus palustris, Linn., Zydroporus palustris, M.C.—Oblongo-ovalis, sat 
convexus, evidenter pubescens, subtus niger, supra fuscus, capite prothoraceque 
lateribus rufis, illo vertice utrinque fusco, elytris basi, signaturisque externis 
testaceis, pedibus rufis, antennis fuscis basi rufo; coxis posterioribus subobsolete 
punctatis. Long. 3%, lat. vix 2 m.m. 
Mas, subopacus, elytris minus distincte punctatis, tarsis anterioribus et inter- 
mediis dilatatis, illo unguiculis inzequalibus, anteriore crassiore et breviore. 
Fem., paulo magis opaca, et indistinctius punctata. 
This is a variable species in size, in the markings, and even in punctuation and 
pubescence. In the mountains of Scotland I have found a reddish form with the 
markings nearly obliterated. 
Europe; Corsica ; Sardinia, (Lapland ; Finland to 69° North, Sahlberg; Britain, France, Geneva; 
Germany; Lithuania; Styria). 344. 
613. Hydroporus vagepictus, Fairm., M.C.—Oblongo-ovalis, evidenter pubescens, 
niger, supra fuscus, capite, prothoraceque lateribus rufescentibus, illo fusco-notato, 
elytris basi lateribusque vage testaceis, sat distincte punctatis, pedibus rufis, 
antennis fusco-rufis, basi rufo; coxis posterioribus parce subobsolete punctatis. 
Long. 4, lat. 2 m.m. 
TRANS, ROY. DUR. SOC., N.S., VOL. II. 3Q 
