346 On Aquatic Carnivorous Coleopiera or DijtiscidoB. 



Grocp 2. 



244. Hydroporus apicatus, Clk., M.C. — Brevis, latus, ovalis, posterius valde 

 acuminatus, castaneo-testaceus, nitidus, glaber ; prothorace basi utrinque strlola 

 subtili ; elytris crebre subtiliter sed distincte punctatis. Long. It, lat. 1 m.m. 



Head very broad, impunctate, clypeus not margined. Thorax almost impunctate, 

 with the hind angles indistinct but a little obtuse. Elytra with fine punctures, 

 which become very indistinct at the sides and extremity. Hind coxce with some 

 moderately coarse punctures, middle of breast quite impunctate. 



I am not quite sure as to the locality of this peculiar little species, but I believe it is St. Do min go. I 

 have only seen two individuals of it. 75. 



245. Bidessus borrei, n. sp. — Brevis, latus, ovalis, valde convexus, posterius 

 acuminatus, nitidus, glaber, castaneo-testaceus, elytris obscurioribus ; prothorace 

 basi utrinque stria subtili, elytris sat crebre subtiliter punctatis ; coxis posterioribus 

 fere impunctatis. Long. 1^ m.m., lat. I m.m. 



This species seems closely allied to Hydroporus apicatus, but it appears to me to 

 have the prosternal process rather broader, it is also considerably smaller, narrower, 

 and more convex, and the elytra are more obscure in colour. 



I have seen only a single individual which is in the collection of the Brussels Museum. It is I believe 

 from Pemambuco, and beai-s a label, " fuscipcnuis, Chev." 76. 



24G. Il^'phydrus acuminatus, Steinheil, Atti. Soc. Ital. Sci. Nat. XII, p. 249. — 

 Brevis, latus, ovalis, convexus, posterius acuminatus, nitidus, glaber, ferrugineus, 

 elytris obscurioribus, prothorace basi utrinque stria subtili ; elytris sat crebre sub- 

 tiliter punctatis ; coxis posterioribus, sparsim distincte punctatis. Long. H, lat. 

 1 m.m. 



Closely allied to Hydroporus apicatus and Bidessus borrei, (Nos. 244 and 245), 

 but has the antennee a good deal thinner than in H. apicatus, and is rather larger 

 and a good deal broader than Bidessus borrei, and has the hind coxse distinctly 

 punctured. 



I am indebted to .M. Steinheil for an authentic example of this interesting species. 



Buenos Avres. 77. 



Group 3. 



247. Hydroporus bicarinatus, Clairville, M.C. — Breviter ovalis, subtus convexus, 

 sine pubescentia, nigricans, thorace medio rufescente, elytris testaceis, sutura 

 fasciisque nigris ; supra dense subtiliter sed evidenter, subtus fortiter profundeque 



