636 On Aquatic Carnivorous Coleoptera or Dytiscide. 
rated before the extremity. The punctuation of the elytra instead of bemg 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- 
in fortiter punctatis ; prosterni processu acuminato, sat elongato ; coxarum pro- 
cessubus rotundatis. Long. 26, lat. 13 m.m. 
Mas, nitidus. 
Fem., 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 shght ; 
the hind coxee in it are also distinctly punctured, and the punctuation of the hind 
femora and tibize 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 epipleurz ; the dark colour seems to be sometimes extended and 
diffused. 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 North 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 posterioribus 
nigricantibus ; angustulus, transversim equaliter 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. 262, lat. 13; m.m. 
