50 MANDIBULATA. — COLEOPTERA. 



Genus CCXCII. — Pachyrhinus, Kirhy. 



^«^e?7wcE geniculated;, ll-jointed, rather short and slender; funiculus 6-jomtedj, 

 its three basal joints rather elongate, and somewhat obconic ; the remainder 

 subnodose, all coarctate ; club oblongs subovate. Rostrum very short, thick, 

 a little bent: eyes large, somewhat rounded, prominent: thorax transverse, 

 convex, narrowed in front, the anterior margin truncate, the posterior deeply 

 bisinuated: scutellum minute: elytra ample, short, ovate, rounded at the 

 apex, shorter than the abdomen : legs rather long, anterior approximating at 

 the base ; femora short, unarmed ; tibiw truncate at the apex, unarmed ; tarsi 

 A'arious. 



Pacliyrliinus may be known from tlie preceding genera by 

 liaviiig the antennse 1 1-jointed, and by wanting a groove beneath 

 the thorax for the reception of the rostrum ; which latter is very 

 stout and rather short : — the species frequent aquatic plants and 

 swim well — whence the name Hydaticus, applied to them by 

 Schonherr (who seems to be unaware of that term having been pre- 

 viously employed by Dr. Leach for a genus of Hydradephaga), 

 which I have been compelled to change to the one proposed by 

 Mr. Kirby. 



A. With the thorax bituberculate. 



Sp. 1. leucogaster. Fuscus, squamulis cinereis tectus, corpore suhtus albido, 

 thorace fusco, lateribus pallidis, elytris fusco-cinereis, striatis. (Long. corp. 

 li-l| lin.) 



Cu. leucogaster. Marsham.—Pa,. leucogaster. Steplu Catal. 158. No. 1609. 



Fuscous, clothed with cinereous scales, beneath whitish : thorax fuscous, with the 

 sides, and a faint dorsal line, whitish ; each side with a minute tubercle: elytra 

 striated, the strife impunctate, fuscous, with an ashy down : legs rufescent, 

 with \\\e. joints black ; antennae rufo-piceous, with the club dusky or black. 



Not common : found in the vicinity of London, and in Somerset- 

 shire. 



Sp. 2. rufescens. Obscure rufo-piceus, subtus cinerascens, thorace carinuM dor- 

 sali squamis albidis tectu, elytris latis i7nmaculatis, suturd bast albidd, antennis 

 pedibusque piceo-r7ifescentibus. (Long. corp. 1| — 1^ lin.) 



Pa. rufescens. Steph. Catal. 159. No. 1610. 



Obscnre rufo-piceous, beneath cinerascent: thorax with an acute tubercle on 

 each side, the disc with a longitudinal central channel, which is clothed with 

 whitish scales : elytra broad, slightly striated, immaculate, with a small 

 whitish patch at the base of the suture : antennoB and legs entirely rufescent. 



