642 On Aquatic Carnivoroxis Culeoptera or DytiscidcB. 



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

 punctatis, prothorace undique crebre sed subtiliter punctate. 



(6), nitida, prothorace vix punctulato, elytris baud sulcatis, ad apicem sat punctatis. 



The male has the small palettes moderately developed, those on the hinder and 

 inner portion however, a good deal longer than the rest ; the palettes on the middle 

 tarsi are quite small. 



The species is excessively similar to D. marginalis, but seems perfectly distinct, 

 the apices of the coxal processes are more prolonged, slender, and acute ; the small 

 palettes on the male front feet are less highly developed, and the punctuation on 

 the thorax of the females is finer. The species seems to vary very little ; the 

 North American individuals show no distinction from the European. The yellow 

 mark on the middle of the head is usually smaller than in D. marginalis, while the 

 eyes in all the individuals I have seen have a yellow margin round them. 



Central Europe, piincipally the North Eastern parts, (Siberia ?); North America. (Sweden ; Finland, 

 61" 50' Sahlberg ; England ; France ; Germany ; Red River). 945. 



996. Dytiscus parvulus, Man., M.C. — Minor, angustulus, subtus testaceus, suturis 

 anguste nigro-cinctis, supra olivaceo-niger, nitidus, prothorace limbo omni elytris - 

 que flavo-marginatis, antennis pedibusque testaceis ; prosterni processu lato, brevi ; 

 coxarum processubus spinoso-acuminatis, sed parum elongatis ; sutura frontali 

 in medio obsoleta. Long. 261, lat. 13 m.m. 



Mas, nitidus, elytris ad apicem sat punctatis. 



Fern., nitida, prothorace versus latera verticeque capitis subopacis, elytris baud 

 sulcatis, ut in mare punctatis et nitidis ; prothorace verticeque sparsim subtilissime 

 punctatis, illo intra latera distincte subimpresso. 



The male tarsi are similar to those of D. dauricus (No. 998) 



The frontal sutu'e in the male is fine, but .still may be distinguished even in the 

 middle, in the female it is more obsolete than in the male. 



Although the species has some points of i-esemblance with D. dauricus, it seems 

 to be a very distinct one ; it is smaller and narrower, the female sculjjture is greatly 

 reduced, and the coxal processes, though quite slender, are less elongate, and com- 

 paratively more distant ; the obsolete h'ontal suture of the female is a very i-emark- 

 able distinctive character for that sex. 



I have seen only one pair of this species ; I believe the two specimens to be really 

 one species, though the sexual difference in the frontal suture appears to be the 

 reverse of what exists in other species. It is doubtful whether Motschulsky's 

 Dytiscus parvulus is this species or D. dauricus, or D. vexatus, but his name may 

 be altogether neglected, his note being an insufficient description. 



North-western North America ; (Kadjalc, Coll. Brussels Mus. and Mnizech). 1139. 



