On Aquatic Carnivorous Coleoptera or Di/tiscidte. 475 



Mas, tarsis anterioribus leviter dilatatis unguiculis vix insequalibus. 



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). 3-iG. 



Gil. Hydroporus incognitus. Sharp, Ent. Mo. Mag. "VI, p. S4. — 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, an tennis rufo-fuscis basi rufo ; coxis 

 posterioribus sparsim punctatis. Long. 3|, lat. vix 2 m.m. 



Has, tarsis anterioribus leviter dilatatis unguiculis vix insequalibus. 



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, is more slender. 



Central Europe, (Britain, Belgium France, Savoy). 345. 



612. Dytiscus palustris, Linn., Hydroporus 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, of, lat. vix 2 m.m. 



Mas, subopacus, elytris minus distincte punctatis, tarsis anterioribus et intei'- 

 mediis dilatatis, illo unguiculis inrequalibus, anteriore crassiore et breviore. 



Fern., 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 J Corsica; Sai-dinia, (Lapland; Finland to GO" 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, 

 autennis fusco-rufis, basi rufo ; coxis posterioribus pai'ce subobsolete punctatis. 

 Long. 4, lat. 2 m.m. 



TRAN9. HOY. DUB. SOC , N.S., VOL. II. 3 Q 



