1014 COLEOPTEKA 



less extent in some of the Bidessi, and in the isolated Sternoiiriscus, 

 and even in some of the Hydroijorini. 



The Hnxelhydrus syntheticus occm'S either in Australia or New- 

 Zealand, and possibly in each of those regions. 



I have made this generic name, as well as Tyndallhydrus, Dar- 

 zvinJtydms, and Spencerhydrus, in reference to some men whose clear 

 thinking and able writing have placed us under a load of obligation, 

 my recognition of which I am glad to express. 



181-6. H. virgatUSj ^^-s. Oblong-oval, subdepressed, slightly 

 shining, closely and finely punctured, with minute grey hairs ; tes- 

 taceous or fusco-testaceous ; most part of the head, tlie frontal and 

 basal margins of the thorax, and the apical portion of all but the two 

 or three basal joints of the antennae fuscous ; there are two blackish 

 stripes on each elytron, these do not reach the base, the outer is 

 shorter than the inner, the latter is often recurved in front of the 

 apex, the suture also is of a dark colour. 



Head with an impression near each eye. Thorax about twice as 

 broad as long, the sides a little curvate before the middle, nearly 

 straight but a little narrowed behind ; there are two oblique basal 

 plicae, and the space on the inside of these is depressed. Elytra 

 narrowed behind, apices obliquely truncate ; at the base there are 

 two short, broad grooves, a little nearer to the middle than the 

 thoracic plica?, and two oblique ones behind the scutellar region ; 

 there are no sutural striae, but the inner dark lines are somewhat 

 depressed, and have on each a series of larger punctures than are seen 

 on most of their surface ; similar punctures occur on the external dark 

 streaks also. 



Underside nigro-fuscous, densely sculptured, and clothed with 

 minute, depressed, grey hairs, but with longer ones near the ex- 

 tremity ; metasternum canaliculate behind ; prosternal process finely 

 asperate, but not much larger proportionally than in Bidessus i)licatus. 



The truncature of the apices of the elytra is a sexual character only. 



Length, 1|- lines ; breadth, -^ line. 



Mount Cook Hermitage. Discovered by Mr. H. Suter. Dr. 

 Sharp's H. syntJietic2is is at present a doubtful New Zealand species, 

 but its description will be found further on along with some other 

 water-beetles. 



Obs. — No. 1689 having been found to belong to the genus Co^jc- 

 latiis, I take this opportunity of renaming it Copelatiis sliarpi, in 

 honour of the author of the work on Dytiscidae. In this species 

 there are no submarginal nor discoidal entire striae on the elytra. 



Group-HYDROPHILID^. 



Saphydrus. 



Nov. gen. 

 {Sharj); Trans. Ent. Sac. Loud., 1884, p. 467.) 

 Ex affinitate generis Hydrobii. Palpi maxillares breves, capite 

 breviores, baud crassi, articulis inter se longitudine parum dissimile. 



