552 On Aquatic Carnivorous Coleoptera or Dytiscide. 
pedibusque rufis, supra subopacus, densius subtiliusque reticulatus, elytris guttulis 
duabus paliidis: coxis posterioribus margine exteriore externe parum curvato. 
Long. 113, lat. 6 m.m. 
The male has the three basal joints of the front and middle tarsi distinctly 
incrassate, and clothed beneath with rather long hairs which bear minute palettes ; 
the anterior claw of the front fect is very nearly simple, while the posterior one has 
its basal portion emarginate beneath and slightly more bent ; the whole of the apical 
portion of the last ventral segment is covered with coarse longitudinal strie, 
without any trace of central carina; the outer claw of the hind foot is accuminate, 
and differs but little from the inner one except that it is much shorter: in the 
female the apical segment is plicate at the apex, and has the appearance of being 
rather deeply notched, and it has two or three rugz on each side. 
The species may be readily distinguished from Dytiscus obscurus by the metallic 
upper surface, and by its rather shorter form, as well as by the different male 
characters. It varies considerably in size and colour, and the individuals I have 
seen from North America seem to vary even more than those from Europe ; but I 
can find no definite characters to distinguish even the extremest specimens that have 
come under my observation. 
Europe ; Arctic Siberia; North America. (Finland to 69°, Sahlberg; Britain?; France; Germany ; 
Jenisei ; Hudson’s Bay ; Canada). 839. 
784. Ilybius pleuriticus, Lec., Agas. Lake Sup. p. 213.—Ovalis, elongatus, vix. 
convexus, subtus piceus et sub-eenescens, supra eeneus, limbo anterius vage ferru- 
gineo, antennis pedibusque quatuor anterioribus rufis, pedibus posterioribus piceis, 
elytrorum epipleuris ferrugineis; suprasub-opacus, densius reticulatus, elytris guttulis 
duabus pallidis ; coxis posterioribus subtiliter strigosulis, margine anteriore externe 
haud subito curvato. Long. 12, lat. 6 m.m. 
The male has the three basal joints of the front and middle tarsi distinctly 
incrassate, and furnished beneath with long hairs which bear distinct rather large 
palettes, the anterior claws are rather elongate and each is a little emarginate near 
the base; the outer claw on the hind foot is rather elongate and thickened, but is 
distinctly shorter than the inner one, its extremity is sub-obtuse, not at all curved ; 
the apical ventral segment has a short carina in the middle at the extremity, and 
is but little rugose on each side: the same segment in the female is plicate, and 
appears to bear a rather deep narrow notch, and is quite without lateral rugosities. 
North America. 840. 
785. Ilybius inversus, n. sp.—Ovalis, haud elongatus, convexus, subtus piceus et 
subeenescens, supra seneus, limbo anterius vage ferrugineo, antennis pedibusque 
quatuor anterioribus rufis, pedibus posterioribus piceis, elytrorum epipleuris ferru- 
