4j-j 0)1 Aquatic Carnivorous Cvleoptcra or DytiscidoB. 



Group 4. 



552. Hydroporus occultus, n. sp. — Oblongo-ovalis, angustulus, nitidus, Isevis, 

 piceus, antennis pedibusque rufis ; prothorace fere impunctato ; elytris parce 

 subtilissime punctatis ; coxis posterioribus sparsim subtiliter punctatis. Long. Si, 

 lat. 1§ m.m. 



This species may be placed not very far from Hyphydrus memnonius, (No. 558) ; 

 but it is a very distinct species, and has the prosternal process more developed than 

 in the H. melanarius allies. 



I have seen but a single individual, which is probably a male, the basal joint of 

 the intermediate tarsus beinar rather laroje. 



Algeria, (Coll. Ott). 400. 



553. Hydroporus occidentalis, n. sp. — Oblongo-ovalis, brevius tenuiter parciusque 

 pubescens, sub-opacus, niger, antennis pedibusque fusco-rufis ; prothorace medio 

 latius sublcevi, limbo minus discrete punctato ; elytris sat crebre subtiliter punctatis, 

 punctis apicem versus obsoletis ; coxis posterioribus sparsim, subtiliter punctatis. 

 Long. 3j, lat. if m.m. 



Very closely allied to Hydroporus longicornis, but the extremely scanty pubescence 

 is rather more visible, and the punctuation of the elytra is closer, and the antenute 

 and legs darker in colour. I have seen only one individual. 



North America, (Lake Labache, British Cohunbia). 398. 



554. Hydroporus longicornis. Sharp, Ent. Mo. Mag. VI, p. 84. — Oblongo-ovalis, 

 fere sine pubescentia, niger, antennis pedibusque rufis, illis gracilibus extrorsum 

 saspius infuscatis ; prothorace medio sublajvi, basi sat crebre punctato, lateribus 

 antrorsum minus angustatis ; elytris parce subtiliter punctatis ; coxis posterioribus 

 parce minus fortiter punctatis. Long. 3f, lat. l| m.m. 



This species is closely allied to Hydroporus melanarius, but is rather narrower 

 and more elongate, and has the elytra more finely punctured, and the thorax is 

 rather differently formed, and the antennce more elongate ; it seems to vary in the 

 surface, being sometimes shining, and sometimes quite dull. The sexes are very 

 difficult to distinguish. 



Europe, (Finland, Scotland, Wales, Savoy,). 397. 



555. Hydroporus melanarius, Sturm, M.C. — Oblongo-ovalis, fere sine pubescentia, 

 niger, vel piceus, antennis pedibusque rufis ; prothorace minus punctato, medio 

 latius subkcvi, basi fere sparsim jjunctato ; elytris parce punctatis, punctis apicem 

 versus obsoletis ; coxis posterioribus parce minus fortiter punctatis. Long. 31, lat. 

 1| ru.m. 



