470 On Aquatic Carnivorous Coleoptera or Dytiscide. 
595. Hydroporus glabriusculus, Aubé, M.C.—Oblongo-ovalis, convexiusculus, 
parcius sed evidenter pubescens, nitidus, niger, capite vix dilutiore, antennis 
pedibusque fusco-rufis, illis basi late rufo; prothorace antrorsum minus angustato, 
angulis posterioribus haud obtusis, sparsim punctato; elytris sat crebre minus 
subtiliter punctatis ; coxis posterioribus sparsim evidenter punctatis. Long. 3, 
lat. 13 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, Thoms., 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 antenne 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; prothorace 
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, Lec., M.C.—Ovalis, parcius sed evidenter pubescens, 
nigricans, pedibus fusco-nigris, antennarum basi minus lete rufo; prothorace 
anterius angustato, basi subtiliter punctato, medio fere impunctato ; elytris parcius 
distincte punctatis, pubescentia bene conspicua; coxis posterioribus sparsim 
punctatis. Long. 33, 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, Hydroporus 
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. Mose. 1853, III, 
p. 163) is assigned as a synonym to this species on the authority of Crotch. 
Russian America. (Siberia ; Sahlberg). 359. 
