wafer-beetles of Japan, 451 



Hydrophilus rufipes. 



The species recorded in Mr. Lewis' catalogue of 

 Japanese Coleoptera as Sternoloplms fidvipes, Motsch., 

 is this species, common in Eastern Asia ; what S. fid- 

 vipes, Motsch., may prove to be I am still unable to 

 determine. 



Hydrocyclus, n. g. 

 Gen. Hydrobio affinis ; corpus rotundatum convexum, palpi 

 maxillares, sat elongati, thoracis longitudiiie, crassiusculi, articulo 

 pseiido-basali recto, articulo iiltimo praecedente lougiore ; mentum 

 magniim, planum, anterius rotundatum, dense sculpturatum. 

 Mesosternum processu elevato, posterius excavato. Pedes tenues, 

 haud natatores, tarsi posteriores subtus pubescentes, baud ciliati. 



This rather curious form can only be placed near 

 Hi/drohius, from which it is readily distinguished by the 

 elongate palpi, and by the clothing of the under surface 

 of the hind feet ; the mesosternal process is peculiar ; it 

 is rather broad, placed transversely with a subacuminate 

 free extremity, and from its hollowed posterior face 

 emits a very slender process, which connects between 

 the middle legs with a narrow prolongation of the meta- 

 sternum. The basal halves of the femora are densely 

 and finely pubescent ; the antennae are nine-jointed, 

 with short club ; one of the anterior tibial spurs is elon- 

 gate and much curved. 



The Chinese genus Hydrocassis, Fairm., is probably 

 an allied form, having, according to the description, a 

 different mesosternal structure. 



Hydrocyclus lacustris. 



Eotundato-ovalis, piceus, antennarum basi, palpis, tibiis tarsisque 

 rufis ; supra fortiter punctato, capita tlioraceque punctis inaequali- 

 bus mixtis ; elytris fortiter seriatim punctatis, interstitiis alternis 

 fortiter, apicem versus subasperate, punctatis, margine laterali dia- 

 tante serrato. Long. 7 mm., lat. 5 mm. 



Head coarsely punctiu'ed, behind with fine punctiu'es between 

 the larger ones, these latter in the middle not extending to the 

 front margin. Thorax very transverse, distinctly margined all 

 round, with numerous distinct irregularly-placed punctures, and 

 with other very fine, more numerous, punctures between these. 

 Elytra with regular series of coarse punctures, which behind and 

 at the sides become strict, and the alternate interstices bear coarse 



