On Aquatic Carnworous Colcoptera or Dytiscide. 611 
927. Rhantus remator, n. sp.—Ovalis, haud convexus, nitidus, subtus niger, 
prosterno rufo, antennis pedibusque testaceis, pedibus posterioribus magis obscuris ; 
supra testaceus, vertice nigro rufoque variegato, thorace in medio late transversim 
fuscescente, elytris crebre nigro-irroratis, tarsis posterioribus brevibus, articulo 
quarto vix perspicue lobato-producto. Long. 103, lat. 54 m.m. 
This species is excessively closely allied to Dytiscus signatus, but I have not 
been able to reduce the individuals ! have seen of it to a variety thereof ; the form 
in the present species is broader in front, and the greatest width is nearer the 
extremity of the elytra, and the black dots of the wing-cases are of larger size, the 
thoracic dark mark is extensive, while in the broader varieties of Dytiscus signatus it 
is always diminished ; the male characters are exceedingly similar, but the claws of 
the middle and tront feet appear a little thicker than in the corresponding sex of 
Dytiscus signatus; it is very probable however that this will prove to be only 
another variety of that variable species. 
South America, (Peru). 876. 
928. Colymbetes vicinus, Aubé, Rhantus vicinus, i/.C.—Ovalis, sat convexus, 
nitidus, niger, supra testaceus, capite nigro anterius et in vertice testaceo, thorace 
in medio vitta transversa nigra, basique plus minusve nigricante, elytris crebre 
nigro-irroratis, antennis pedibusque rufis, illis extrorsum, et femoribus preesertim 
posterioribus, infuscatis; tarsis posterioribus haud brevibus, articulo 4° gracili 
brevius lobato-producto, unguiculo interno quam externo dupio longiore. Long. 
9%, lat. 5 m.m. 
The male has the basal joints of the front and middle tarsi a good deal in- 
crassate and compressed, and clothed beneath with moderately small palettes ; the 
front claws are unequal, the anterior being moderately long, and rather thick, 
with well marked basal lobe, the hind one a good deal longer, and thickened 
between the hase and middle; the claws of the middle feet are thick beneath and 
rather short and nearly equal: the female often has the thorax very deeply sinuate 
at the sides close to the front angles. 
South America, (Columbia). 877. 
929. Rhantus advena, n. sp.—Ovalis, sat angustus, haud convexus, nitidus, subtus 
niger, prosterno in medio piceo, supra testaceus, capite nigro-rufoque variegato, 
thorace in medio vitta transversa nigra, basique nigricante, elytris creberrime nigro 
irroratis, antennis testaceis articulo ultimo infuscato, pedibus rufis, femoribus infus- 
catis ; tarsis posterioribus haud brevibus, articulo 4° gracili posterius lobato-producto, 
unguiculis parum elongatis, crassiusculis, interno quam externo haud duplo longiore. 
Long. 10, lat. 5 m.m. 
TRANS. ROY. DUB. SOC., N.S., VOL. II. es HS 
