On Aquatic Carnivorous Coleoptera or Dytiscide. 451 
Mas, antennis articulis intermediis dilatatis. 
This species is very similar to Hydroporus formosus, but has the thorax red 
across the middle. It varies in the extent of the black marks on the elytra. The 
Algerian H. Leprieuri (Reiche, Ann. Fr. 1864, p. 235) is, I consider, a variety of 
this epecies. 
Southern Europe, (Sicily, Corsica), Algeria. 322. 
i. 
537. Dytiscus lineatus, Fab., Hydroporus lineatus, M.C.\—Ovalis, convexus, 
posterius acuminatus, parce subtiliter punctatus, evidenter pubescens, testaceus, 
prothorace anterius et posterius elytrisque infuscatis, his lineis indistinctis margineque 
exteriore testaceis; corpore subtus nitido, coxis posterioribus fortiter punctatis. 
Long. 3, lat. 12 m.m. 
Mas, tibiis anterioribus intus versus basin angustatis, tarsis anterioribus et 
intermediis evidenter dilatatis. | 
This species varies in the distinctness of the lines on the elytra, which are some- 
times nearly obliterated. In Corsica there occurs a small dark form, in which the 
male characters are less developed than usual : in the examples from the Continent 
of Europe, the basal joint of the middle tarsus is conspicuously dilated, but in the 
small Corsican form it is only very slightly so. JI have however seen some 
specimens (also I believe from Corsica) which appear intermediate in these respects. 
'The male of this species is not quite so dull on the upper surface as the female. 
Europe ; Corsica ; common in Continental Europe; extends in Finland to 68° North, according to 
Sahlberg. 323. 
538. Hydroporus vicinus, Aube, M.C.—Ovalis, convexus, posterius acuminatus, 
parce subtiliter punctatus, evidenter pubescens, supra fusco-testaceus limbo 
dilutiore ; subtus testaceus, nitidus, coxis posterioribus fortiter punctatis. Long. 
34, lat. 12 m.m. 
Mas, sat nitidus, evidenter punctulatus, tarsis anterioribus et intermediis latis. 
Fem., opaca, obsolete punctata, tarsis anterioribus et intermedius sat latis. 
This species though very closely allied to Dytiscus lineatus, is more obscure in 
the colour of its upper surface, and appears to me really distinct ; the distinctions 
of the sexes being undoubtedly different. 
Tangiers. 324. 
539. Hydroporus genei, Aubé, M.C.—Ovalis, convexus, posterius acuminatus, 
subtiliter punctatus, evidenter pubescens, subnitidus, ferrugineus, prothoracis basi 
elytrisque infuscatis, his macula basali limboque laterali irregulari pallidis ; corpore 
subtus nitido, coxis posterioribus fortiter punctatis. Long. 34, lat. 17 m.m. 
TRANS. ROY. DUB. SOC., N.S., VOL, II. 3 N 
