550 On Aquatic Carnivorous Colcoptera or Dytiscide. 
801. Ilybius oblitus, n. sp.—Ovalis, fere brevis, convexus, subtus piceus, supra 
nigro-eneus, limbo anterius minus ferrugineo, antennis pedibusque rufis ; supra 
subopacus, elytris densius reticulatis, guttulis duabus, quarum posteriore conspicua, 
pallidis ; coxis posterioribus crebre evidenterque strigosulis, margine anteriore ad 
coxam intermediam approximato extus abrupte longeque deflexo; prosterni 
processu brevi. Long. 103, lat. 6 m.m. 
The male has the basal joints of the front and middle tarsi distinctly incrassate, 
and furnished beneath with rather long hairs, which bear distinct palettes, the claws 
of the front feet are elongate and sinuate, the hinder one of the two especially is 
slender and much sinuate; on the hind feet the outer claw is elongate, slender and 
very acuminate, similar in fact to that of the female ; the last ventral segment is 
almost without carina or rugosities ; in the female the same segment is, com- 
paratively with D. biguttulus (No. 797), but little deflexed-emarginate at the 
extremity. 
Though singularly similar to Dytiscus biguttulus this species is readily dis- 
tinguished therefrom by the greater approximation of the front border of the hind 
coxa to the middle coxal cavity. 
North America. 856. 
802. Dytiscus fenestratus, Fab., Ilybius fenestratus, M.C_—Ovalis, convexus, 
ferrugineus, supra eeneus, limbo ferrugineo, supra subnitidus, densius reticulatus, 
elytris ad medium versus latera guttula elongata testacea ; coxis posterioribus fere 
esculpturatis, margine anteriore ad coxam intermediam approximato, extus per- 
abrupte longeque deflexo ; prosterni processu fere brevi. Long. 113, lat. 6 m.m. 
The male has the basal joints of the front aud middle tarsi distinctly incrassate, 
and furnished beneath with long hairs bearing distinct palettes ; the claws of the 
front feet are long, the anterior one being thickened beneath except on the 
outer portion which is very acuminate, the hinder one is not quite so long, and 
is slender and subsinuate ; the outer claw on the hind feet is thickened, subobtuse, 
and considerably shorter than the inner one ; the last ventral segment has the hinder 
part rugose, with a strongly elevated carina in the middle ; in the female the hinder 
part of this segment is very deeply deflexed-emarginate. 
Colymbetes prescotti, Mann. (Ilybius prescotti, Aubé), is a red variety of this 
species found in the north. | 
Kurope, (Sweden ; Finland to 60° 10’ Sahlberg; Britain; France; Germany.) 857. 
803. [lybiuscinctus (Sharp), n. sp.—Minor, ovalis, subnitidus, testaceus, supra seneus, 
capite anterius thoraceque ad latera ferrugincis, elytris margine lato ad apicem triha- 
mato testaceo, densius subtiliusque punctato-reticulatis ; coxis posterioribus fere 
