On Aquatic Carnivorous Coleopteixt or Dj/tiscidce. 553 



gineis ; supra subnitidus, crebvius vix subtiliter reticulatus, elytris guttulis duabus 

 (quarum anteriore elongata et conspicua) testaceis ; coxis posterioribus subtiliter 

 strigosulis, margine anteriore externa baud subito curvato. Long. 12^, lat. 6^ m.ni. 

 The species difters from Iljbius pleuriticus, by its more convex less parallel form 

 and the different reticulation of the upper surface. I have one mutilated individual 

 only of the male before me, its sexual characters seem to be quite the same as in I. 

 pleuriticus, but its hind feet being quite gone I cannot speak positively on this 

 point ; the female has the apical notch broader than it is in I. pleuriticus. The 

 form of the species makes it very similar to I. subseneus, but it is readily dis- 

 tinguished therefrom by its more shining and coarser reticulated upper surface, and 

 by the rather more slender outer portion of the metasternal wings. 



North America. 841. 



786. Ilybius quadrimaculatus, .-\ube, M.C. — Ovalis, sat elongatus, minus convexus, 

 subtus niger, supra nigro-ceneus, antetmis rufis, articulis 7-10 extrorsum infuscatis, 

 pedibus piceis, elytris guttulis duabus te&taceis, epipleuris nigro-aeneis, supra sub- 

 opacus, densius subtiliter reticulatus ; coxis posterioribus subtilius strigosulis et 

 punctatis, margine anteriore externe baud abrupte curvato. Long. 11^, lat. 6 m.m. 



The male has three basal joints of the front and middle tarsi, distinctly incrassate, 

 and furnished beneath with moderately long hairs, which bear small palettes ; of 

 the front claws the anterior one is slightly thickened, and nearly straight beneath, 

 while the hinder one is a good deal emarginate near the base ; on the hind feet the 

 outer claw is nearly similar in form to the inner one, except that it is a good deal 

 shorter ; the last ventral segment, has a much elevated carina on the middle of its 

 apical portion, and is also coarsely rugose ; the female has the last segment also 

 carinate, and appearing to bear only a very small notch, and is without rugosities. 



The species is of a more black colour than its near allies. 



North America. 842. 



787. Ilybius crassus, Th., M.C. — Ovalis, baud elongatus, convexus, subtus nigri- 

 cans, supra nigro-Eeneus, antennis pedibusque anterioribus rufis, posterioribus piceis ; 

 elytris subopacis, densius reticulatis, punctis subseriatis conspicuis ; coxis posteri- 

 oribus subtiliter strigosulis, margine anteriore extus sat abrupte curvato. Long. 

 Hi, lat, 6 J m.m. 



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

 furnished beneath with moderately long hairs bearing small palettes ; the claws o7^ 

 the front feet are moderately long, and nearly simple, the hinder one being how- 

 ever distinctly emarginate near the base ; the outer claw on the hind foot is thick- 

 ened, and subobtuse at its apex, without any deflexed point ; the male has no 



