642 On Aquatic Carniworous Coleoptera or Dytiscide. 
Fem. (a), subopaca, elytris ad basin ultra medium suleatis, ad apicem crebrius 
punctatis, prothorace undique crebre sed subtiliter punctato. 
(b), nitida, prothorace vix punctulato, elytris haud suleatis, 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, principally 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 fiavo-marginatis, antennis pedibusque testaceis ; prosterni processu lato, brevi ; 
coxarumm processubus spinoso-acuminatis, sed parum elongatis; sutura frontali 
in medio obsoleta. Long. 263, lat. 13 mm. 
Mas, nitidus, elytris ad apicem sat punctatis. 
Fem., nitida, prothorace versus latera verticeque capitis subopacis, elytris haud 
sulcatis, ut in mare punctatis et nitidis ; prothorace verticeque sparsim subtilissime 
punctatis, illo intra latera distinete subimpresso. 
The male tarsi are similar to those of D. dauricus (No. 998). 
The frontal suture in the male is fine, but still nay be distinguished even in the 
middle, in the female it is more obsolete than in the male. 
Although the species has some points of resemblance with D. dauricus, it seems 
to be a very distinct one ; it is smaller and narrower, the female sculpture is greatly 
reduced, and the coxal processes, though quite slender, are less elongate, and com- 
paratively more distant ; the obsolete frontal suture of the female is a very remark- 
able distinctive character for that sex. 
I have seen cnly 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 whut 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 ; (Kadjak, Coll. Brussels Mus. and Mnizech). 1139. 
