On Aquatic Carnivorous Coleoptera or Dytiscidce. 615 



937. Rhantus anisonychus, Crotch, Tr. Am. Ent. Soc. IV, p. 409. — Ovalis, fere 

 elongatus, safe convexus, sat nitidus, subtus niger, supra testaceus, vertice nigro- 

 variegato, prothorace in disco maculis duabus coalescentibus nigrls, elytris 

 creberrlme nigro-irroratis, antennis testaceis, extrorsum parum infusuatis, pedibus 

 piceo testaceis : prothorace margine laterali sat discreto ; tarsis posterioribus sat 

 gracilibus, unguiculo interno quam externo duplo longiore ; metasterni laciniis 

 extrorsum brevibus. Long. Hi, lat. 6 m.ro. 



The male has the front and middle tarsi a good deal incrassate, and moderately 

 compressed, with the under surface bearing large palettes, and the marginal hairs 

 largely developed and curled at their terminations ; the front claws are excessively 

 elongate, appearing when viewed from the front quite slender, the anterior one is 

 much longer than the other and is slightly bisinuate beneath ; the middle claws are 

 thick, the outer being much longer than the more curved inner one : the female 

 has the lateral portion of the wing cases from the shoulder to the middle, and also 

 the lateral portion of the thorax, with the reticulate sculpture much deeper. 



North America, (California). 885. 



938. Rhantus discedens, n. sp. — Ovalis, fere elongatus, sat couvexus, subtus 

 piceo-rufus, capite in medio prosternoque rufis, supra testaceus, capite nigro, anterius 

 rufo, prothorace plaga transversa discoidali nigra, elytris creberrime nigro-irroratis, 

 antennis pedibusque rufis, illis extrorsum ieviter fuscescentibus ; prothorace lateribus 

 curvatis, margine laterali sat discreto; tarsis posterioribus subrobustis, artieulo 

 quarto vix lobato-producto, unguiculo interno quam externo plus duplo longiore : 

 metasterni laciniis brevibus. Long. Hi-, lat. 6 m.m. 



I have seen but a single female of this, which is no doubt a veiy distinct species ; 

 this individual has the basal portion of the elytra covered with deep coarse im- 

 pressions, rendering the surface very rugose, the apical half of the wing cases 

 bearing the usual fine reticulations ; the thorax has on each side a large patch of 

 coarse sculpture. 



North America, (Cailfornia). 886. 



939. Colymbetes atricolcr, Aubd, M.C. — Ovalis, niger, nitidus, vertice testaceo- 

 bimaculato, antennis rufis, pedibus piceis ; supra crebrius punctate reticulatus, 

 subtus Isevigatus, nitidus, neque strigosulus nee punctatus ; prothoracis margine 

 laterali subobsoleto : tarsis posterioribus robustis, articulis baud lobato-productis, 

 unguiculo externo elongate, quam interno baud duplo breviore. Long. 14, lat. 

 7J m.m. 



The male has the basal joints of the front and middle tarsi a little incrassate, and 

 greatly compressed, and clothed beneath with rather long hairs and four rows of 



