Mr. G. R. Waterhouse on some Heteromerous Cokoptera. 317 



XXXV. — Descriptions of some new genera and species of Hetero- 

 mei'ous Coleoptera. By G. R. Waterhouse, Esq. 



Platesthes, nov. gen. 



Head rather short, the lateral lobes or ridges protecting the base 

 of the antennse, less prominent than the eye. 



Chjpeus separated from the head by a distinct transverse impres- 

 sion, and by two less distinct lateral grooves ; the anterior mar- 

 gin slightly emarginated. 



Eyes transverse, convex, rather large and distinctly emarginated 

 in front. 



Lahrum prominent, transverse, distinctly emarginated in front. 



Mandibles moderate, bidentate at the apex. 



Maxillce with the outer lobe entirely uncovered by the mentum : 

 the maxillary palpi moderate, the terminal joint triangular. 



Labial palpi short and stout, the terminal joint truncated. 



Mentum broader than long, four-sided, the hinder margin di- 

 stinctly shorter than the front, which is obscurely emarginated, 

 but nearly straight. 



Labium transverse, corneous, exposed. 



Throat-plate^ with a narrowish oblong polished and transversely 

 grooved area in the middle, joining the mentum by a straight 

 margin. 



Antennce rather long and slender ; if extended backwards would 

 nearly reach the base of the thorax ; the joints, most of them, 

 of a long obconic form ; the second joint short, the third scarcely 

 longer than the fourth ; the three terminal joints distinctly 

 broader than the rest, the last of a short ovate form and equal 

 to the penultimate. 

 Thorax large, very nearly equal in width to the elytra, and nearly 

 quadrate, but slightly narrower in front, the outer edge emar- 

 ginated, the posterior margin very nearly straight, and not 

 closely applied to the elytra ; the angles nearly right angles, 

 but slightly rounded ; the upper surface slightly convex in the 

 middle, but the lateral margins are recurved ; the whole dorsal 

 surface however is pretty nearly flat. 

 Scutellum very broad, but rather short, and obtusely pointed be- 

 hind. 

 Elytra soldered together at the suture ^ oblong ; the dorsal sur- 

 face nearly flat, the sides parallel, but on the posterior third 

 gradually contracted, so that the outline of that region w^ould 

 form half an oval ; the apex however is produced, recurved and 



* This part, which I term throat-plate^ often furnishes somewhat import- 

 ant characters : it is the mesial part of the head beneath, below (or behind) 

 the mentum. 



