Water Beetles of Japan. 57 
wlien well examined, the elytra are found to possess traces 
of a sparing and obsolete scattered punctuation. Each 
elytron is armed near the extremity with two sharp mode- 
rately long s])ines, one placed quite at the extremity near 
the suture, the other at the side at a five or six times 
greater distance from the suture. The under surface, as 
well as the legs, is entirely pale yellow. 
Abundant in Nipon and Kushiu. I also possess speci- 
mens of this species from Mantchuria. 
Hydeophilid^. 
29. Ili/drophilus copnatus,n.sp. Ovalis, nigro-olivaceus ; 
palpis antennarumque basi testaceis, harum clava fusca ; 
elytris stitura spina apicali minuta instructis; abdomine 
segmentis medio carinatis. Long. 17 — 18 lin. ; lat. 9 lin. 
Mas, tarsis anterioribus articulo 5°, precedente paulo 
latiore. 
This species is greatly allied to our European H. piceus, 
but is quite distinct therefrom ; it is about the size of 
aterrimus; it has a minute spine at the extremity of the 
elytra, as in piceus, and all the segments of the abdomen 
are carinated along the middle. The sternal spine is 
deeply canaliculate in Iront, and again before the ex- 
tremity ; the portion projecting over the base of the 
abdomen is unmistakably shorter than in H. piceus ; this 
character, with its smaller size, will enable the female to 
be distinguished from that of M. piceus ; the male cannot 
be confounded with H. piceus, the slightly dilated joint of 
the front tarsi and the comparatively small and less un- 
equal unguiculi being very different from our European 
species. 
Abundant in Nipon and Kushiu. 
I possess this species fi-om China and Formosa. I have 
not been able to see Motschoulsky's description of H. 
acuminatus fi'om China.* 
30. Hydrophilus japonicus, n. sp. Anguste - ovalis, 
minus convexus, supra viridi-olivaceus, plus minusve 
metallescens ; elytrorum sutura apice denticula minuta ; 
palpis antennisque rufis ; subtus niger, abdomine lateri- 
bus fulvo-maculato ; processu sternali elongato ; abdomine 
* Since this was written I have seen the description referred to, and 
consider it inapplicable to either of the two species of Hydropliilus here 
described. D. S. 
