On Aquatic Carnivorous Coleoptera or Dytiscide. 529 
but is considerably larger, and the rugosity of the apical ventral seement in the 
male is much greater. The few specimens before me show a little variation in the 
leneth of the prosternal process, and in the size of the metasternal groove. 
Northern Europe, (Germany ; France ; a very rare species). 774. 
743. Agabus nigro-eneus, Er., Kaf. Mark. I, p. 157.—Oblongo-ovalis, sat 
convexus, minus nitidus, niger, supra nigro-zneus, prothoracis elytrorumque 
marginibus obscure ferrugineis, antennis rufis, pedibus piceis; elytris dense con- 
spicueque reticulatis. Long. 10, lat. 5% m.m. 
The male has the front and middle tarsi a good deal incrassate, and the three 
basal joints furnished beneath with rather long glandular hairs, some of which are 
developed into distinct palettes: on the anterior feet the front claw has the basal 
portion a good deal thickened, while the posterior one is a good deal emarginate 
beneath near the base: the apical ventral segment bears deep oblique furrows, 
which scarcely extend to the flattened or depressed middle portion: the claws of 
the hind tarsi are shorter and stouter in the male than in the female: and in the 
former sex the three basal joints of the hind tarsi are provided beneath with 
swimming hairs, while in the males of the allied species such hairs are confined to 
the first joint. 
Northern Europe, Siberia, North America; (Sweden ; Finland; France; Germany; Hudson’s Bay 3 
Canada; California). 776. 
744. Agabus subtilis, Er., M.C.—-Ovalis, sat convexus, minus nitidus, niger, supra 
nigro-zeneus, antennis rufis, pedibus piceo-rufis ; elytris densius subtiliusque reticulatis. 
Long 95, lat. 5¢ m.m. 
The male has the front and middle tarsi a good deal incrassate, and the three 
basal joints rather thickly furnished beneath with moderately long glandular hairs, 
some of which are developed into minute palettes ; the anterior claw of the front 
feet 1s a good deal thickened im its basal portion, while the posterior one is slightly 
emarginate near the base : the apical ventral segment is deeply strigose longitudinally 
on each side of the middle : the hind tarsi in the male also are peculiar in form and 
greatly approximate to what prevails in the genus Ilybius, the fourth joint being 
externally a little lobed at its lower posterior angle, while the fifth joint is thicker 
than in the female, and has its lower edge emarginate, and the claws shorter, thicker, 
and more unequal than in the female. 
The species greatly resembles Agabus neglectus, but it is larger, and the males 
are readily distinguished by the structural peculiarities ; the females are extremely 
similar, and except for the larger size of A. subtilis it would be very difficult to 
distinguish them : A. subtilis p has however the minute punctuation on the apical 
