On Aquatic Carnivorous Coleoptera or Dytiscid(B. 529 



but is considerably larger, and the rugosity of the apical ventral segment in the 

 male is much greater. The few specimens before me show a little variation in the 

 length of the lirosternal process, and in the size of the metasternal groove. 



Northern Europe, (Germany ; France ; a very rare species). 774. 



743. Agabus nigro-peneus, Er., Kaf. Mark. I, p. 157. — Oblongo-ovalis, sat 

 convexus, minus nitidus, niger, supra nigro-asneus, prothoracis elytrorumque 

 marginibus obscure ferrugineis, antennis rufis, pedibu^ piceis ; elytris dense con- 

 spicueque reticulatis. Long. 10, lat. 5f 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, Nortli America ; (Sweden ; Finhind ; France ; Germany ; Hudson's Bay } 

 Canada J California). 776. 



744. Agabus subtilis, Er., M.C. — Ovalis, sat convexus, minus nitidus, niger, supra 

 nigro-seneus, antennis rufis, pedibus piceo-rufis; elytris densius subtiliusque reticulatis. 

 Long 95, lat. 5i m.m. 



The male has the front and middle tarsi a sfood deal inci-assate, 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 is a good deal thickened in 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 



