170 D. Sharp: Three new Water-ßeetles. 



Three new Water-Beetles. 



By D. Sharp. 



i. Bidessus nasutus. 



Breviter ovalis, sat convexus, nitidus^ nigricans^ antennis ex 

 parte majore , pedibus , elytrorumque signaturis testaceis ; elytris 

 fortiter punctatis ; clypeo anterius quasi hituberculato. Long. 2 mm. 



This is of short form for the genus, with the pubescence 

 extremely reduced and the surface shining ; there is a deep 

 plica on each side of the thorax, and a deep rather elongate 

 continuation of this on the wing-cases. There ig a sutural 

 Stria notextending more tban half the length of the elytra. 

 The clypeus has the front a little incrassate on either side 

 adjacent to the eye , and in the middle two peculiar minute 

 elevations of the surface. The thorax is infuscate at the base 

 and is scarcely at all punctate across the middle, but is some- 

 what eoarsely punctate at the base and more ünely near 

 the front margin. The punctuation is quite coarse on the basal 

 portion of the elytra but becomes quite fine and dense at the 

 apex : the yellow markings, consist of a b.road irregulär fascia 

 a little behind the base, widest at the outer margin and 

 interrupted at the suture, and of a yellow mark on each side 

 at the apex. The undersurface is shining and has coarse punctu- 

 ation on the coxa. 



Government of Orenburg, one example, Europe ; near 

 Vienna. 



This is the insect refered to in my description of Hydro- 

 porus pumilus as possibly a distinct species. The Central Asian 

 exponent is even smaller and narrower than the European 

 examples and I have now little doubt that it is distinct from 

 -ET. pumilus Aub^. 



2. Octhebius laevigatus. 



Niger, antennis palpis pedibusque testaceis, capite thoraceque 

 metallescentibus ; elytris livide testaceis, impunctatis. Long, l^j^mm. 



Allied to 0. margipallens and 0. martnus but readily 

 distinguished by the unsculptured upper surface. The head 

 has two large deep foveae on the Vertex. The thorax is strongly 

 transverse , only slightly narrowed behind, the basal portion 

 of the side bordered with a very slender with transparent 

 membrane, the surface impunctate, a transverse depression in 

 front of the middle and another behind, the surface duU and 



