OF NEW ZEALAND. 77 



Group HYDROBIDXE. 



Lobes of the maxilla membraneous or coriaceous. Antenna with 

 eight, seldom with nine joints. Pro thorax as wide as- the elytra at the 

 base, narrowed in front. The four posterior tarsi not reniform, slightly, 

 or not at all, compressed, ciliated or not on their dorsal edge ; the basal 

 joint short, obliquely truncated at the end, the second longest of all. 

 Without sternal carina. 



Hydrobius. 



Leach; Lacord. Hist, des Ins. Coleop., Tom. i.,/. 455. 



Mentum transversal, rounded in front, straight at the sides. Palpi 

 slender ; the labial short, last joint obconical or oval, shorter than the 

 preceding ; the maxillary long, their last joint longer than the penulti- 

 mate. Mandibles membraneous, and ciliated inwardly. Labrum trans- 

 versal, rounded in front. Head large, or wide, obtuse in front, with 

 the epistome truncated or hollowed. Eyes large, slightly prominent. 

 Antenna nine-jointed, the first large, depressed and arcuated j second 

 rather long, conical ; joints three to five very short, nodiform ; -sixth 

 smooth, hornlike, annexed to the following ; seventh to ninth forming 

 an elongate club, moderately compact. Prothorax transversal. Scutellum 

 rather large, triangular. Elytra oval, subparallel, or almost hemi- 

 spherical, and convex. Legs moderate ; femora compressed, the tro- 

 chanters of the posterior narrow and not projecting ; tibia slender, 

 spinulous ; the four hind tarsi feebly compressed, long, and sparingly 

 pilose, their hooks simple. Mesosternum with a narrow keel between 

 the intermediate coxae ; the metasternum convex in the centre. 



Body oviform, more or less short, convex, sometimes almost hemi- 

 spherical. 



143. H. zealandiCUS, n.s. Oblong-oval, moderately convex, black, 

 shining, legs red, palpi reddish-testaceous, antennae rather shining, 

 reddish, their club infuscate. 



Maxillary palpi quite as long and stouter than the antennae, their last 

 joint longer than the second, thickest near the apex. Antenna with the 

 two basal joints stout; joints three to five rather slender, the third 

 longest ; sixth joint transverse, as broad as the base of the club, which 

 is large. Head obtusely rounded, epistome truncate in front ; it is a 

 little convex, rather closely punctured, with two indistinct lines con- 

 verging towards the middle, and a more or less distinct depression near 

 each eye. Prothorax transverse, finely margined, its apex bisinuated, 

 the base obtusely rounded towards the scutellum with a sinuation at 

 each side of it ; the sides are a little rounded, and narrowed anteriorly, 

 with the front and hind angles obtuse ; its punctation is rather dense 

 and fine, but becomes coarser towards the margins. Scutellum punc- 

 tated. Elytra hardly three times longer than thorax, indistinctly 

 margined, each with ten rows of not very large punctures, the intervals 

 are punctated, and some, notably the third, bear some rather larger 



