434 On Aquatic Carnivorous Coleoptera or Dytiscidce. 



490. Hydroporus ceresyi, Aube, M.C. — Ovalis, angustulus, elytris dense 

 breviterque pubescentibus, fere opacus ; subtus niger, supra testaceus, protborace vel 

 concolore vel indisiincte nigro-notato, elytris sutura lineisque baud confluentibus 

 nigris ; j^rothorace lateribus obliquis, postice latiore angulis posterioribus acutis ; 

 corjDore dense subtilissime punctulato. Long. 4|, lat. 21 m.m. 



The male has the front and middle tarsi a good deal broader than the female. 



The lines on the elytra are often much diminished and are sometimes nearly 

 absent : in other specimens the lines are broader, and then become connected 

 together here and there by spot-like dilatations. 



South Europe and North Africa; (South France, Sardinia, Spain, Mogador, Egj^it). 261. 



491. Deronectcs suffusus, n. sp. — Ovalis, baud nitidus, subtus niger, supra ex 

 testaceo nigroque coloratus, elytris lineis valde confluentibus nigris ; corpore dense 

 subtilissime punctulato, sculptura prothoracis disci parciore et minus subtili ; 

 subtus subtilissime reticulato. Long. 4", lat. 2i m.m. 



Very closely allied to Deronectes prosternalis, but not so acuminate behind, with 

 the sculpture of the prothorax not so fine and even, and with the carina of the 

 presternum less elevated in front. 



I have seen only a single individual, in bad condition. 



North America, (Coll. Bonvouloir). 270. 



492. Deronectes prosternalis, n. sp. — Ovalis, breviter sed evidentor pubescens, 

 baud nitidus, subtus niger, supra ex testaceo nigroque coloratus, elytris lineis valde 

 confluentibus nigris ; corpore dense subtilissime punctulato, subtus subtilissime 

 reticulato ; prosterno ante coxas evidenter carinato-clevato, carina anterius abrupta. 

 Lono'. 41, lat. 2]- m.m. 



I see scarcely any external sexual distinctions. 



This species is extremely similar to the European Dytiscus griseostriatus, (No. 

 493), but is distinguished by the considerably stronger carination of the presternum 

 in front of the anterior coxte. I have examined about a dozen individuals to assure 

 myself of the validity of this character. 



North America. 269. 



493. Dytiscus griseostriatus, de Geer, Hydroporus griseostriatus, M.C. — Ovalis, 

 angustulus, evidenter pubescens, sub-opacus, subtus niger, supra testaceus, capite 

 utrinque, prothoracis signaturis elytrisque lineis septem elongatis nigris ; supra 



