466 On Aquatic Carnivorous Coleoptcra or Dytiscidce. 



greater or less development in tlie longitudinal direction ; the external or humeral 

 one may be extended far backwards along the edge of the wing-case. 



Mediterranean region, (Tangier, Andalusia). 4 1 ] 



582. Dytiscus marginatum, Duft., Ili/Jroporiis marginaliis, 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. 4^, lat 2i 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 retrorsum 

 spectantibus, basi lateribusque fortiter, medio sparsim punctato ; elytris sat crebrc, 

 conspicue punctatis ; coxis posterioribus punctis magnis, profundis. Long. 4, 

 lat. 2l m.m. 



Mas, nitidus, elytris fortiter punctatis, tarsis anterioribus et intermediis fortiter 

 dilatatis, illis unguiculis elongatis. 



Fem., opaca, elytris conspicue sed minus fortiter punctat's. 



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 2i, 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 



