ivater-beetles of Japan. 449 



executed plates it is now possible to determine with 

 certainty the species of this very difficult family. 



Found in the lake of Chiuzenji about the end of 

 August, 1881. 



Orectochilus agilis. 

 Anguste-ovalis, fusco-niger, elytrorum margine externo angustis- 

 sime, epipleuris pedibusque, ferrugineis, supra sequaliter piinctato 

 tomentoso, capite lievi ; subtns piceus ; elytris apice subrecte trun- 

 cate, angulis externis obtusis ; labro sat producto, rotundato. Long. 

 6Jmm., lat. 3 mm. 



This is another species very distinct from any yet de- 

 scribed, being about the same size as 0. villosus ; it is 

 ruuch less convex, more regularly oval, and it is at once 

 distinguished by the yellow margin of the wing-cases ; 

 the outer apical angle of the wing-case is not broadly 

 rounded, as in 0. villosus, but the hind margin, being 

 nearly straight, the side meets it so as to form a slightly 

 obtuse angle. The male front tarsi are a good deal 

 dilated, and the outer apical angle of the tibia is 

 rounded. 



A good series was taken in the river at Kumamoto about 

 the end of May, 1881, but most of the examples are 

 very immature. Eough weather had occurred, and the 

 specimens had taken refuge under weed on the beach. 



Orectochilus punctipennis. 

 Ovalis, angustus, convexus, supra niger, subsenescens, nitidus, 

 undique punctato-tomentosus, punctatura minus obsoleta, subtus 

 piceus, abdomine flavescente, pedibus testaceis, labro sat producto, 

 rotundato; elytrorum apice oblique truncato, angulo externo 

 rotundato-obtuso. Long. 5^ mm., 2| mm. 



Closely allied to 0. villosus, auct., rather smaller and 

 narrower and scarcely so convex, but at once to be dis- 

 tinguished by the (for this genus) unusually coarse 

 punctuation of the elytra ; the outer apical angle of the 

 wmg-cases is also less broadly and completely rounded 

 than it is in 0. villosus. The dilatation of the male 

 front feet is rather less than it is in 0. villosus, the apex 

 of the tibia is similarly formed. The only two examples 

 found are both rather immature, and show, especially 

 the female, slight traces of some longitudinal depressions 

 on the posterior part of the wing-cases. 



