On Aquatic Carnivorous Coleoptera or Dytiscide. 613 
posterioribus gracilibus, articulo 4° gracili, unguiculo externo parvo quam interno 
triplo breviore. Long. 103, lat. 53 m.m. 
This species seems to be very closely allied to Colymbetes divisus, but has the 
anterior band of and the middle part of the prosternum yellow (the large posterior 
side pieces being black) and the coxal processes of more ordinary form; the male 
characters seem quite the same ; there is no sexual difference of sculpture. 
Russian America ; British Columbia. 880. 
932. Rhantus obscurus, n. sp.—Ovalis, elongatus, haud convexus, sat nitidus, 
subtus niger, supra testaceus, vertice rufo nigroque variegato, thorace in medio 
maculis duabus transversim extensis, elytris creberrime nigro-irroratis, antennis 
fusco-testaceis basi testaceo, pedibus ru‘o-fuscis, posterioribus fere nigris, tarsis 
gracilibus, unguiculo extzrno parvo quam interno triplo breviore. Long. 102, lat. 
53 m.m. 
I see very little to distinguish this species from Rhantus longipes, except the 
colour distinctions ; the black spots on the thorax have assumed a greater trans- 
verse extension, the prosternum is nearly quite black, and the legs are darker ; the 
male characters seem to be the same as in Colymbetes viciaus and Rhantus longipes, 
and there is no sexual difference in sculpture. 
North America, (California). 881 
933. Rhantus suffusus, n. sp.-—Ovalis, clongatus, haud convexus, subtus niger, 
supra testaceus, vertice rufo-nigroque variegato thorace in medio fascia transversa 
nigro-fusca, elytris creberrime nigro-irroratis, antennis pedibusque testacels ; tarsis 
posterioribus parum gracilibus, unguiculo interno quam externo duplo longiore. 
Long. 11, lat. 6 m.m. 
I have not seen the male of this species; the female has the upper surface finely 
reticulate, and there is an elongate patch of coarse reticulation on the wing-case 
behind the shoulder. 
In this species the prosternum is nearly black, except at the sides, and the wings 
of the metasternum are rather short. It will probably prove to be closely allied 
to R. anisonychus (No. 937), but it is smaller and narrower, and the sexual sculpture 
of the female is less developed. 
Mexico, (discovered by Mr. Flohr). 1163. 
934. Rhantus plebeius, n. sp.—Ovalis, sat elongatus, haud convexus, sat nitidus, 
prosterno testaceo, pectore nigro, abdomine femine rufo, nigro-fasciato, maris magis 
nigricante, supra testaceus, vertice nigro-variegato, thorace medio maculis duabus 
transversim extensis nigris, elytriscreberrime nigro-irroratis, pedibus testaceis ; 
tarsis posterioribus sat gracilibus, unguiculo interno crassiusculo quam externo fere 
. e 0 0 . 3 3 
triplo longiore ; prothorace margine laterali bene discreto. Long. 11, lat. 54 m.m. 
4K 2 
