On Aquatic Carnivorous Coleoptera or DyfAscidce. 613 



posterioribus gracilibus, articulo 4*^ gracili, unguiculo externo parvo quam interno 

 triplo breviore. Long. lOi, lat. 5i m.in. 



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 ; Biitish Columbia. 880. 



932. Rhantus obscurus, n. sp. — Ovalis, elongatus, baud convexus, sat nitidus, 

 subtus niger, supra testaceus, vertice rufo nigrcjque variegato, thorace in medio 

 niaculis duabus transversim extensis, elytris creberrime nigro-irroratis, antennis 

 fusco-testaceis basi testaceo, pedibus rufo-fuscis, posterioribus fere nigris, tarsis 

 gracilibus, unguiculo ext&rno parvo quam interno triplo breviore. Long. lOi, lat. 

 5^ 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 vicinus and Rhantus longipes, 

 and there is no sexual difference in sculpture. 



North America, (California). 881 



933. Rhantus suffusus, n. sp.— Ovalis, elongatus, hand convexus, subtus niger, 

 supra testaceus, vertice rufo-nigroque variegato thorace in medio fascia transversa 

 nigro-fusca, elytris creberrime nigro-irroratis, antennis pedibusque testaceis ; tarsis 

 posterioribus parum gracilibus, unguiculo interno quam externo duplo longiore. 

 Long. 11, lat. 6 ni.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. 



Li 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, baud convexus, sat nitidus, 

 prosterno testaceo, pectore nigro, abdomine feminse rufo, nigro-fasciato, maris magis 

 nigricante, supra testaceus, vertice nigro- variegato, thorace medio maculis duabus 

 transversim extensis nigris, elytris creberrime nigro-irroratis, pedibus testaceis ; 

 tarsis posterioribus sat gracilibus, unguiculo interno crassiusculo quam externo fere 

 triplo longiore; prothorace margine laterali bene discreto. Long. 11, lat. 5i m.m. 



4 K 2 



