On Aquatic Carnivorous Coleopicra or Dytiscidce. 437 



Group 1. 



495. Hydroporus aulicus, Aube, M.C. — Oblongo-ovalis, posterius angustatus, 

 sparsim subtilissime pubescens, nitidulus, brunneo-ferrugineus, elytris fasciis duabus 

 transversis maculaque apicali testaceis ; corpore sat crebre et fortiter punctato. 

 Long. 6, lat. 3 ra.m. 



I have seen only two individuals of this large and remarkable species ; they are 

 both in very decayed condition, but appear to be of different sexes, although the 

 distinctions are but slight ; in the male the front tarsi ar.e just distinctly broader 

 than in the female, and the fourth joint is a little longer, and its anterior claw is 

 incrassate. In each sex the antennae are quite slender, but those of the male are 

 distinctly longer than those of th.e other sex. 



The species is remarkable from its large size, and peculiar form, the head being 

 broader than usual, and by its quite distinctly separated hind coxal cavities ; the 

 margin of the thorax is very broad. 



North America, (from Dejean's collection). 271. 



496. Hydroporus diversicornis, n. sp. — Ovalis, sat angustus, parcius subtiliter 

 pubescens, sat nitidus, ferrugineus, prothorace antice et postice elytrisque sutura 

 signaturisque transversis fuscis ; prothorace baud tenuiter marginato ; elytris sat 

 crebre et sat fortiter punctatis ; coxis posterioribus sat crebre fortiter punctatis, 

 nitidis. Long. 4i, lat. 21 m.m. 



Mas, tarsis anterioribus et intermediis .bene dilatatis, antennis majusculis, 

 articulis intermediis crassioribus. 



The male is a little larger than the female, and besides the antennal development, 

 has all the legs thicker than in the female. The claws of the front tarsi are 

 almost equal, and differ but little from those of the female. 



This species was sent me by Dr. Leconte as being the II. aulicus, but it is quite 

 distinct from that remarkable species and connects it with the H. concinnus group ; 

 the coxal cavities are contiguous, though scarcely absolutely so ; the coxal lines 

 are approximate and not bent outwards in front, but at the apex are more divergent. 



North America, (Texas). 288. 



497. Hydroporus concinnus, Lee, M.C. — Ovalis, subtilissime pubescens, nitidulus, 

 fere impunctatus, testaceus, abdomine pectoreque nigricantibus, prothorace anterius 

 et posterius elytrisque infuscatis, his fasciis latis, vagis, interrnptis testaceis ; 

 elytris stria suturali sat distincta ; coxis posterioribus sat crebre obsolete punctatis. 

 Long. 3|, lat. If m.m. 



The only individual I have seen is no doubt a male, as it has the front tarsi 

 moderately dilated. 



3 L 2 



