494 On Aquatic Carnivorous Coleoptera or Dytiscidce. 



Group 1. 



Outline of thorax very discontinuous icith elytra; jirosternum but little thickened 

 in the middle in front ; swimming legs elongate and slendei", their femora feeble, 

 with rounded postero-external angle ; metasternal cavity ill-developed. 



Six species, from both Old and New Worlds. 



662. Agabus (Anisomern) cordatus, 'Lec.jAnisomera cordata, M. C. — Suboblongus, 

 depressus, niger, supra senescens, capite rufescente, anteuuis tarsisque 4 anterioribus 

 geniculisque rufis ; prothorace transverso, basi fere truncato, elytris angustiore, 

 lateribus sinuatis, anterius rotundati?, angulis posterioribus rectis. Long. 11, lat. 

 5 m.m. 



This species is very readily recognized by the form of the thorax. The legs are 

 slender, and the claws elongate ; the sculpture is that of the Agabus guttatus allies. 

 I have seen but a single individual which is a male, and has the three basal joints 

 of the front and middle tarsi a little thickened, and furnished beneath with glandular 

 hairs. 



North America, (Kansas). 720. 



663. Agabus cephalotes, Reiche, M.C. — Fere oblongus, depressus, nigro-piceus, 

 nitidus, antennis pedibusque rufis, prothoracis lateribus dilutioribus ; prothorace 

 elytris angustiore, lateribus antrorsuui subrotundatis, posterius leviter angustatis, 

 angulis posteiioribus paulo obtusis ; superficie baud coriaceo ; elytris punctis magnis 

 posterius irregularibus, antrorsum in seriebus tribus ductis. Long. 9i, lat. 41 m.m. 



The shining surface and peculiar form of this species render its recognition very 

 -easy. There is no difference of sculpture in the sexes ; in the male the two basal 

 joints of the front and middle tarsi are scarcely thickened, but are furnished beneath 

 with glandular hairs. 



Corsica. 721. 



664. Agabus caraboides, n. sp. — Fern., Ovalis, fere depressus, niger, antennis pedi- 

 busque concoloribus,elytrisfuscis; prothorace basi quam elytris evidenter angustiore, 



Brulle (No. 1207); Chili. — Colymbetesannulatus, Zoiil>. (No. 1212); Turconiania. — Colymbetes bicolor, 

 Kirh. (No. 121.5); North America. — Colymbetes impressns, Zoub. (No. 123I); Tiircomania. — 

 Colymbetes latus, Gebl. (No. 1236) ; Siberia. 



The position of the following species is quite doubtful : — Agabus hydroporoides, Murr. (No. 1191) ; 

 West Africa. 



