On Aquatic Carnivorous Coleoptera or Dytiscidce. 641 



rounded ; the prosternal process is slightly shorter and broader. It would thus 

 appear that this female in structure a good deal resembles D. pisanus, with an 

 approximation towards D. marginalis, and with the punctuation almost similar to 

 (the smooth female of) that species. 



Persia; found (I believe at Ispakiu) bv the Marquis Jacques Doria in 1862 or '63. 943. 



994. Dytiscus marginahs, Linn., M.C — Subtus testaceus, metasterno in medio 

 nigricante, supra nigro-olivaceus, prothorace limbo omni elytrisque lateribus flavo- 

 marginatis, antennis pedibusque rufis, tarsis posterioribus plus minusve picescenti- 

 bu>; prosterni processu lato, hand elongato, coxarum processubus brevibus, sat 

 acuminatis. Long. 33, lat. 18 m.m. (Long. 26-34 m.m.) 



^fas, nitidus, elytris ad apicem sat punctatis. 



Fern, [a), subopaca, elytris ad basin ultra medium sulcatis, ad apicem crebrius 

 et fortius punctatis, prothorace undique crebrius parum subtiliter punctato. 



(b), nitida, prothorace subopaco, undique subtiliter punctulato, elytris apicem 

 versus crebrius quam in mare punctatis. 



The male has the siBall palettes on the front feet large and highly developed, those 

 near the two large cups being especially large and distinct, those on the middle feet 

 are very small, but still are to be distinctly distinguished. The species varies a 

 good deal in size, the females being particularly liable to reduction in this respect, 

 and it also varies in the colour of the undersurface, the ventral segments being 

 occasionally much marked with black. Except for these points and the sexual 

 discrepancies, the species shows but little variation ; the individual from Japan 

 is, however, a very broad one, and appears to me to have the small cups of the front 

 male tarsi rather less developed than in the European specmiens. 



This species is comparatively widely distributed in Europe, it occurs within the 

 Arctic circle, (68°, Sahlberg), and as far south as Geneva, Lombardy, and Trente, 

 and Hautes Pyrenees. It has not been recognized as occurring in America, but I 

 have a female individual labelled, "Am. bor.int., montagnes rocheuses," by Castlenau; 

 and found an individual said to be from North America, in Murray's collection. 



Europe, Siberia, Japau, North America. 944. 



Group 2. 



995. Dytiscus circumcinctus, Ahr., M.C.— Subtus testaceus vel ferrugineus, 

 metasterno in medio obscuro, supra nigricans, prothorace limbo omni elytrisque 

 flavo-marginatis, antennis pedibusque rufis, tarsis posterioribus picescentibus; pro- 

 sterni processu lato, baud elongato; coxarum processubus apicibus breviter prolon- 

 gatis, angustatis et acuminatis. Long. 32, lat. 16 m.m. 



Mas, nitidus, elytris ad apicem pavum punctatis. 



