28 Mr. G. H. Waterhouse on Coleopterous Insects 



Head small^ in width not equal to more than half that of the 

 thorax ; inclosed in the thorax as far as the eyes ; the outline 

 of the part in front of the eyes, including the mandibles and 

 labrum, is conical, but taking the arch formed by the outline 

 of the clypeus, it is nearly semicircular ; — slightly indented on 

 each side of the clypeus. 



Antennce of moderate length ; if extended backwards would 

 scarcely reach the base of the thorax; slender, the joints of a 

 long obconic form ; the second joint short, the third long, but 

 not equal in length to the two following joints taken together; 

 the last three joints dilated ; the antepenultimate and penulti- 

 mate present a triangular outline ; the last joint is about equal 

 in size to these, but of an oval form. 



Eyes tolerably large and moderately convex, kidney-shaped, being 

 very slightly encroached upon in front by the lateral ridge of 

 the head. 



Thorax transverse, narrower before than behind, rather deeply 

 emarginated in front, rounded at the sides and bisinuated be- 

 hind, where it is closely applied to the thorax : the upper sur- 

 face is convex, and there is an impressed line (not very distinct) 

 following the margins, but interrupted in the middle of the 

 anterior margin : the angles are acute in front and right 

 angles behind, — or nearly right angles. 



Scutellum rather small, but distinct ; rounded behind. 



Elytra soldered together, very convex, broader than the thorax 

 and of an ovate form, but sinuated in front, where the curved 

 outline corresponds to that of the hinder margin of the thorax ; 

 the humeral angles somewhat obtuse. 



Presternum with its hinder margin obtuse, notched, and not pro- 

 duced posteriorly beyond the anterior coxae. 



Abdomen but little inclosed at the sides by the elytra. 



Le^s slender and moderately long ; the tibiae nearly cylindrical, 

 and terminated by two small spines : tarsi slender ; the hinder 

 tarsi equal in length to more than two-thirds of that of the 

 tibia. 



In general appearance the species of this genus greatly re- 

 semble those of the genus Helops, and more particularly those 

 shorter-bodied species of which our common Helops striatus may 

 be said to form the type. In size and general form, the Stomion 

 Icevigatus (hereafter described) greatly resembles the insect just 

 mentioned, but its thorax and elytra are more convex. The Sto- 

 mion galapagoensis is half as large again as the H. striatus, and 

 of a much broader form and more convex above : the third species 

 of Stomion known to me is considerably less than the H. striatum, 

 and of a shorter and broader form. The structure of the mouth, 



