On Aquatic Carnivorous Coleoptera or Dytiscide. 531 
legs very approximate, so that the metasternal groove is excessively narrow and 
indistinct. 
North America, (Oregon, Vancouver's Island). 790. 
Group 20. 
Coxal border very wide ; the coxal lines gently, not abruptly, turned outwards at 
the extremity ; prosternal process punctulate, slightly raised along the middle. 
Four species from both Old and New Worlds. 
748. Agabus melanarius, Aubé, Spec. p. 353, Agabus tarsatus, M.C.—Oblongo- 
ovalis, niger, sat nitidus, supra haud perspicue senescens, antennis rufis, pedibus 
piceis ; fortiter conspicue reticulatus, prothorace lateribus vix rotundatis, angulis 
posterioribus obtuse rectis ; prosterni processu punctulato medio glabro. Long. 9, 
lat. 5 m.m. 
The male has the three basal joints of the front and middle tarsi a little 
thickened, and furnished beneath with very short glandular hairs: the anterior 
claw of the front foot is slightly thickened, and its lower margin a little sinuate. 
Northern Europe. (Sweden, Finland, Denmark, Germany, Russia). 730. 
749. Agabus tristis, Aube, M.C.—Oblongo-ovalis, superne minus convexus, sat 
nitidus, fusco-niger, prothoracis lateribus, et vitta transversa post marginem anterio- 
rem, elytrisque humeris plus minusve discrete rufescentibus, antennis pedibusque rufis, 
posterioribus plus minusve infuscatis, corpore subtus plus minusve rufo-variegato ; 
supra undique evidenter reticulatus reticulis magnis. Long. 103, lat. 5$ m.m. 
The male has the three basal joints of the front and middle tarsi much incrassate 
and amply furnished beneath with short glandular hairs: the claws of the front 
feet are moderately long, and are scarcely at all more developed than in the female, 
but the anterior one has a tooth at its extreme base: there is a slight difference 
in the sculpture of the sexes, the female having the scratches on the basal portion 
of the elytra placed in a rather more regular and oblique direction, and the meshes 
formed by them are more elongate. 
The species varies a good deal in colour. 
Russian America: Arctic Siberia, (Dudinka, Sahlberg). 791. 
750. Agabus wollastoni, n. sp.—Mas et femina perdissimiles ; oblongo-ovalis, 
minus convexus, subtus niger, antennis palpis pedibusque rufis; supra undique 
subtiliter sed evidenter reticulatus ; prothorace basi elytrorum latitudine, lateribus 
obliquis, minus rotundatis, angulis posterioribus vix obtusis. Long. 11, lat. 6 m.m. 
TRANS. ROY. DUB. SOC., N.S., VOL. II. 3 Z 
