636 On Aquatic Carnivorous Coleoptera or Dytiscidce. 



rated before the extremity. The punctuation of the elytra instead of being dense 

 towards the apical portion, as in D. punctulatus, is much more scanty, and is of a 

 peculiar character, being somewhat coarse and yet indistinct, and also somewhat 

 transversely rugulose. 



•Japan. 981. 



985. Dytiscus fasciventris, Say, M.C. — Subtus ferrugineus, nigro-variegatus, 

 supra nigricans, prothoracis elytrorumque lateribus flavo marginatis, antennis pedi- 

 busque rufescentibus, tibiis tarsisque picescentibus ; elytris posterius crebrius 

 punctatis, pedibus posterioribus minus gracilibus, femoribus maris obsolete fem- 

 inee fortiter punctatis ; prosterni processu acuminato, sat elongato ; coxarum pro- 

 cessubus rotundatis. Long. 26, lat. 13 m.m. 



Mas, nitidus. 



Fern., parum nitida crebrius punctata, elytris ad basin ultra medium sulcatis. 



The male has the small palettes of the front feet small but distinct, and larger 

 than those on the middle feet which are quite small. The female has the sides of 

 the thorax a good deal punctured, but the punctuation on the middle is very slight ; 

 the hind coxae in it are also distinctly punctured, and the punctuation of the hind 

 femora and tibioe is much greater than in the male ; the differences between the 

 sexes are very marked and constant. 



The species is subject to considerable variation in size, and to some in coloration ; 

 occasionally the hind and front margins of the thorax are vaguely yellowish ; the 

 colour of the undersurface is generally reddish, with the middle of the metasternum 

 and sutures of the breast blackish, and the ventral sutures are generally narrowly 

 black, the dark colour being dilated into a blotch on each side, but not extend- 

 ing to the epipleurse ; the dark coluur seems to be sometimes extended and 

 diflused. Though undoubtedly allied to D. punctulatus, the species is readily 

 distinguished by the different colour, by the stouter hind legs, with different 

 punctuation on the femora, by the greater development of the small palettes on 

 the front feet of the male, and the unabbreviated eighth interstice of the female. 



Eastern Nortli America. United States and Canada. 936. 



986. Dytiscus habilis. Say, M.C. — Subtus ferrugineus, nigro-variegatus, supra 

 nigricans, prothorace limbo omni late flavo, elytris margine flavo ad apicem dilatato 

 et fere diviso, antennis pedibusque rufescentibus, tibiis tarsisque posterioi'ibus 

 nigricantibus ; angustulus, transversim aequaliter convexus; pedibus posterioribus 

 robustis, femoribus glabris ; prosterni processu angusto, elongato, apice minute 

 recurvo ; coxarum processubus rotundatis ; elytris versus latera paulo ultra medium 

 longitudinaliter impressis. Long. 26?, lat. ISj m.m. 



