6 Dr. D. Sharp's descriptions of Japanese Coteoptera. 



and stands apart trom the transverse band, which is undulated. On the 

 under surface of secondaries the central black spot is small, and the costal 

 one is not directly above, but placed nearer the base. Expanse, 64 mm. 



Chang- Yang. One female example captured by a native 

 collector. 



DESCEIPTIONS OF TWO NEW SPECIES AND A NEW 

 GENUS OF JAPANESE COLEOPTERA. 



By Dr. D. Sharp, F.R.S., &c. 



The two insects here described belong to families of Coleo- 

 ptera the Japanese species of which have been recently all worked 

 out. These two descriptions serve the purpose of keeping the list 

 np to date, 



Rhantus yessoensis, n. sp. (Dytiscidce). 



Major, latus, niger, supra testaceus, elytris crebrerrime nigro-irroratis, 

 sutura marginibusque externis pallidis, capitis vertice maculaque ad mar- 

 ginem oculi, prothoracis maculis discoidalibus nigi-is. Parum nitidus, elytris 

 creberrime minute reticulatis : pedibus rufis, femoribus posterioribus pices- 

 centibus. Long. 14 mm. 



This fine species of Rhantus is, like R. erraticus, peculiar on 

 account of the minute reticulation of the surface being less 

 obsolete than is usual in the genus. It differs from R. erraticus 

 by the colour of the legs, and b_y the spot on the disc of the 

 thorax not being expanded transversely, as well as by the male 

 characters: the front and middle feet in this sex are broadly 

 dilated, and the anterior claw is much longer than the posterior; 

 on the middle foot the anterior claw is also much dilated, and both 

 it and the hinder claw are sinuate beneath, in such a way as 

 to leave a short, slender extremity to the claw. The posterior 

 femora are picescent along the middle to a greater or less extent. 



Junsai, two specimens ; Chiuzenji, one specimen : all of the 

 male sex. 



Syncosmetus, nov. gen. (Colydiidce.) 



Corpus breve, valde convexum. Antennae breves, lO-articulatse, clava 

 magna triarticulata. Oculi parvi fortiter prominuli. 



First joint of antennae long and stoui ; second much smaller, but little 

 broader tlian long ; third small and slender, very small at the base, longer 

 tlian broad ; joints 4 — 7 very minute ; 8, 9, and 10 forming a large, very abrupt 

 club. Head small, epistome with a slightly raised margin on each side over 

 the insertion of the antennse, extending as far as the eye ; in the middle 

 without margin. Eyes quite small, but convex and rather coarsely facetted, 

 not hispid. Antennal grooves short and deep. Palpi small, terminal joint 

 acuminate ; labium quite small, so that the slender labial palpi are very 

 approximate. Prosternum elevated and compressed along the middle. Front 

 coxae moderately separated. Middle and hind coxae about as widely separated 

 as the anterior. Metasternum rather short. Hind-body small. First ventral 

 segment much longer than the following, 2 — 4 very short, equal ; terminal 



