470 On Aquatic Carnivorous Coleoptera or Dijtiscidce. 



595. Hydroporus glabriusculus, Aube, M.C. — Oblongo-ovalis, convexiusculus, 

 parcius sed evidenter pubescens, nitidus, niger, capite vix dilutiore, antennis 

 pedibusque fusco-rufis, illis basi late rufo ; protliorace antrorsum minus angustato, 

 angulis posterioribus haud obtusis, sparsim punctato ; elytris sat crebre minus 

 subtiliter punctatis ; coxis posterioribus sparsim evidenter punctatis. Long. 3, 

 lat. U m.m. 



In each sex the front and middle tarsi are broad, but in the male they are 

 distinctly broader than in the female. The species is extremely similar to H. 

 acutangulus, Thorns., but has the punctuation and pubescence less close, and the 

 thorax not so broad behind. 



A specimen from North America (Massachusetts), I -believe may be considered 

 a variety of this species : it has the punctuation and pubescence scarcely less close, 

 and the legs and antennae redder, the head and sides of the elytra more dilute in 

 colour. 



Eastern Siberia, Angara, Lapland. 361. 



596. Hydroporus acutangulus, Thoms., Vet. Ac. hand, 1854, p. 202. — Oblongo- 

 ovalis, convexiusculus, evidenter pubescens, nitidus, niger, pedibus fusco-rufis, 

 antennarum basi late rufo, capite humerisque paulo dilutioribus ; protliorace 

 antrorsum angustato, subtiliter, (in disco parcius) punctato ; elytris crebre subtiliter 

 punctatis : coxis posterioribus sat crebre evidenter punctatis. Long, vix 3, lat. 

 1| m.m. 



The front tarsi are rather broad in the female, and still broader in the male. 



Lapland and Siberia. 360. 



597. Hydroporus tartaricus, Lee, M.C. — Ovalis, parcius sed evidenter pubescens, 

 nigricans, pedibus fusco-nigris, antennarum basi minus Irete rufo ; protliorace 

 anterius angustato, basi subtiliter punctato, medio fere impunctato ; elytris parcius 

 distincte punctatis, pubescentia bene conspicua ; coxis posterioribus sparsim 

 punctatis. Long. 3i, lat. 2 m.m. 



The male has the front and middle tarsi broader than the female, they being 

 slender in the latter sex ; the claws of the front ones are but little unequal, the 

 anterior one being stouter but scarcely shorter. The species is allied to 

 Hydroporus morio, but is larger and more regularly oval in form, and has the 

 punctuation of the thorax a good deal finer. According to Schaum, Hy'droporus 

 geniculatus Thoms. is synonymous with this species, but Thomson says the anterior 

 claw of his species is dentate, and I should be rather inclined to consider that it 

 will prove to be a variety of H. morio. H. nigellus, Mann. (Bull. Mosc. 1853, III, 

 p. 163) is assigned as a synonym to this species on the authority of Crotcli. 



Kussian America. (Siberia ; Sahlberg). 359. 



