On Aquatic Caruivovo'ts Colcoptcva or Dyti'scidcB. 555 



deflexed, acute apex ; the apical ventral segment bears a rather short carina, but 

 no lateral rugosities. 



This species though excessively similar to Dytiscus guttiger, seems to differ by 

 the more sinuate anterior claws of the male, and the less thickened and less obtuse 

 outer claw of the hind foot, as well as by other slight distinctions. 



North America. 847. 



790. Ilybius aenescens, Th. Op. Ent. II, p. 125. — Ovalis, hand elongatus, subde- 

 pressus, fere opacus, subtus nigricans, prosterno elytrorumque epipleuris rufo- 

 obscuris, supra feneus, capite anterius prothoracisque lateribus rufescentibus. 

 antennis pedibusque rufis ; elytris densius subtiliter reticulatis, punctis subseriatis 

 minus conspicuis, guttulisque duabus testaceis indistinctis ; coxis posterioribus 

 obsoletissime strigosulis et punctatis, margins anteriore extus fere abrupte deflexo ; 

 impressione metasternali minus elongate. Long. Sj, lat. 4| m.m. 



The male has the basal joints of the front and middle tarsi slightly incras.sate, 

 and furnished beneath with moderately long hair.s bearing minute palettes; the 

 anterior claws are simple ; on the hind feet the outer claw is but little shorter than 

 the inner, and has a subacute apex ; the apical ventral segmunt has a very short 

 carina at the ape.\', and no distinct rugosities ; in the female the last ventral segment 

 bears a rather broad but not deep emargination, in the middle of which there is 

 almost no projection. 



The species is excessively closely allied to Dytiscus guttiger (No. 788), but besides 

 the slight differences in colour and sculpture, the sexual characters are also a little 

 dissimilar. 



Northern Europe, Siberia ; (Sweden ; Finland, to (56° 30', Sahlberg ; Scotland, Belgium, France, Germany, 

 Lithuania). 848. 



791. Dytiscus angustior, GylL, Ilyhius unrjustior, M.C. — Ovalis, subdepressus, 

 subopacus, niger, .supra seneus, antennis pedibusque rufis, illis articulis 7-10 

 ssepius extrorsum infuscatis, elytris densius .subtiliter reticulatis, punctis subseriatis 

 minus conspicuis, guttulis duabus testaceis indistinctis ; coxis posterioribus sub- 

 tiliter strigosulis, margiue anteriore externe leviter deflexo ; {irosterni processu 

 apice miiuis vlongato. Long. 9i, lat. 5 m.m. 



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

 and furnished beneath with niodorately long hairs which bear minute palettes ; 

 the claws of the front feet are simjile : on the hind feet, the outer claw is shorter 

 than the inner, and is obtusti at the extremity ; the apical ventral segment 

 has a rather sharply elevated carina, and is rugose with elongate coarse striae. 

 In the female the last ventral segment has an emargination at the apex, in the 

 middle of which there is a coarse fold or plica. 



TBANS. ROV. DUB. SOC, >'.9 , VOL. U. ^ n 



