water-beetles of Japan. 443 



at the base, the punctuation of the wing-cases is ex- 

 tremely indistinct, and there are two more or less 

 distinct longitudinal series of impressed punctures. The 

 confluent black lines leave the base and apex pale, as 

 also some lateral spots, and one or two on the disc. 

 The sexual characters are very slight, but there is 

 apparently a slight dilatation of the front and middle 

 tarsi of the male. 



A series of eighteen specimens was found in rivers 

 and streams at Sapporo. 



Deronectes hostilis. 



Oblongo-ovalis, nitidus, testa,ceus, prothorace utrinque plaga 

 fusca, elytris lineis nigris, hie inde maculis pallidis interruptis, 

 ornatis ; prosterno pectore abdomineque nigris ; antennarura 

 palporumque apicibus fuscis ; prothorace lateribus curvatis, anguHs 

 posterioribiis obtusis. Long. 4^ mm. 



Mas, tarsis anterioribus dilatatis unguiciiHs elongatis. 



This is very similar to D. simplicipes, but has the 

 sides of the thorax differently shaped, the black marks 

 of the upper surface are less extensive, and the male 

 feet more largely developed. 



A single example was received from Japan by Mr. 

 Lewis in 1874. The locality, South Kiushiu. 



Hydroporus natrix. 



Late ovaHs, snbdepressus, subopacus, niger, fronte in medio, 

 prothoracis fascia transversa elytrisque guttis rotundatis testaceis, 

 antennis pedibusque fusco-testaceis; supra subtihssime punctulato, 

 punctisque majoribus sparsis, prsetereaque in elytro singulo seriebus 

 duabus puuctorum. Long. 3 — 3^ mm. 



Body entirely without pubescence ; antennae pale yellow, infus- 

 cate externally ; the upper surface with pallid marks, vix., a large 

 round spot on the middle of the head, four such spots placed 

 transversely at the base of the wing-cases, a second transverse 

 series of four spots (of which, however, the two inner are most 

 frequently absent) across the middle, two other spots (also fi-e- 

 qnently wanting) behind these, and a small one quite at the 

 extremity ; the thorax has a transverse pale fascia of variable 

 width across the middle. 



This species belongs to Group 3 of the genus, but 

 cannot be placed in any of the subsections of that 



