560 On Aquatic Carnivorous Cokopicra or Di/liscidie. 



SOI. Ilybius oblitus, n. sp. — Ovalis, fere brevis, convexus, subtus pieeus, supra 

 uigro-ieneus, limbo anterius minus ferrugineo, antennis pedibusque rufis ; supra 

 subopacus, elytris densius roticulatis, guttulis duabus, quarum posteriore conspicua, 

 pallidis ; coxis posterioribus crebre evidenterque strigosulis, margine anteriore ad 

 coxam intermediani approximato extus abrupte longeque deflexo ; prosterni 

 processu brevi. Long. \0h, lat. 6 m.m. 



The male has the basal joints of the front and middle tarsi distinctly incras?ate, 

 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 tlie 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 witli i). biguttulus (No. 797), but little deflexed-emarginate at ihe 

 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., lUjhius t'enesfratus, M.C. — Ovalis, convexus, 

 ferriigineus, supra reneus, limbo ferrugineo, supra subnitidus, densius reticulatus, 

 elytris ad medium versus latera guttula elongata testacea ; coxis posterioribus fere 

 esculpturatis, margine anteriore ad coxam intermediani approximato, cxtus per- 

 abrupte longeque deflexo; prosterni processu fere brevi. Long. Hi, lat. 6 m.m. 



The male has the basal joints of tlie front aiid 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 vontral 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, Aube), is a red variety of this 

 species found in the north. 



Europe, (Sweden ; Finlaad to 60" lO'Sahlberg; Brituiu ; France; Germany.) 857. 



803. Ilybiuscinctus(Sharp), n. sp. — Minor, ovalis, subnitidus, testaceus, supra seneus, 

 oapite anterius thoraceque ad latera ferrugineis, elytris margine lato ad apicem triha- 

 mato testacco, densius subtiliusque punctato-reticulatis ; coxis posterioribus fere 



