466 On Aquatic Carnivorous Coleoptera or Dytiscide. 
ereater or less development in the longitudinal direction ; the external or humeral 
one may be extended far backwards along the edge of the wing-case. 
Mediterranean region, (Tangier, Andalusia). 411 
582. Dytiscus marginatus, Duft., Hydroporus marginatus, M.C.—Ovalis, minus 
convexus, dense subtilissime pubescens et punctatus, subopacus, niger, capite antice 
et in vertice thoracisque lateribus rufis, elytris testaceis medio latius fusco, pedibus 
antennisque rufis, his apicem versus fuscis: coxis posterioribus abdomineque 
omnium dense subtilissime punctatis, opacis. Long. 43, lat. 22 m.m. 
In the male the front and middle tarsi are a good deal broader than in the 
female. The species is very easily distinguished by its sculpture; it varies 
considerably in the colour of the upper surface, the infuscation of the elytra and 
thorax being sometimes very much less in extent, and sometimes indeed almost 
absent, so that the upper surface appears nearly entirely yellow: while the other 
extreme in which the upper surface is nearly entirely dark seems to occur more 
rarely. 
Central and Southern Europe ; from the south of England to Spain, and Italy. 412. 
583. Hydroporus sibiricus, Sahl., n. sp.—Oblongus, convexus, sparsim sed con- 
spicue pubescens, fortiter punctatus, fulvo-testaceus, thorace in medio elytrisque 
fuscis; prothorace antrorsum augustato, angulis posterioribus fere retrorsam 
spectantibus, basi lateribusque fortiter, medio sparsim punctato ; elytris sat crebre, 
conspicue punctatis; coxis posterioribus punctis magnis, profundis. Long. 4, 
lat. 25 m.m. 
Mas, nitidus, elytris fortiter punctatis, tarsis anterioribus et intermediis fortiter 
dilatatis, illis unguiculis elongatis. 
Fem., opaca, elytris conspicue sed minus fortiter punctatis. 
The colour varies in the amount of infuscation, especially beneath. 
Siberia, (Irkutsk ; Jenisei 69°—70° 30'; August, 1876, Sahlberg). 374. 
584. Hydroporus despectus, n. sp.—Ovalis, sat convexus, tenuiter pubescens, 
niger, supra fuscus, sat nitidus, pedibus obscure rufis, antennis fuscis basi rufo ; 
prothorace limbo sat punctato, disco angustius fere impunctato ; elytris sat fortiter 
punctatis ; coxis posterioribus sat crebre et fortiter punctatis; abdomine (basi 
excepto) sparsim subtiliter punctato. Long. 4, lat. vix 25, m.m. 
Though this and the four following species do not offer any striking cha- 
racters, and are not easy to distinguish, I think they will all prove distinct. A 
