MONOPLATUS. 7 



dencia (the English boarding-house kept by the late Mr. Land, 

 Organ Mountains), during the visit of Mr. Gray and myself in 

 February 1857. The species differs from nigripes and distinguendus 

 (to both of which it is closely allied) by the coloration of its head 

 and legs : from nigripes it is structurally separated by its transverse 

 and linear fovea between the eyes, by its rectilinear (and not sub- 

 sinuate) transverse canaliculation at the base of the thorax, and by 

 the less deep emargination of the anterior margin of the thorax ; 

 from distinguendus it differs by its concolorous elytra, and by the 

 absence of any spot on the crown of the head. The three species, 

 although unquestionably closely allied, appear to me to have ample 

 marks of difference which separate them each from the others. 



3. Monoplatus distinguendus. (TAB. I. fig. 2.) 



M. oblongus, subparallelus, niger, nitidus ; capite brevi, impunctato, 

 ferrugineo ; thorace transverso, rectangulari, antice subemargi- 

 nato, angulis anterioribus prominulis depressis, apud basin 

 fovea lineari transversa ornato, impunctato, flavo ; elytris par- 

 allelis, subdepressis, punctato-striatis, ad basin paulum elevatis, 

 nigris, ad humeros flavo-marginatis ; antennis filiformibus, art. 

 1-4 ferrugineis, reliquis nigris ; pedibus flavis, tarsis tibiisque 

 apicalibus nigris. 



c? Long. corp. 3 lin., lat. 1J lin. 



Oblong, subparallel, subdepressed, black, shining. Head short, 

 transverse, hardly produced ; eyes large, prominent, black, occupying 

 a considerable portion of the head ; between the eyes is an obsolete 

 longitudinal impression ; ferruginous. Thorax broader than the head, 

 transverse, in front slightly emarginate (not so distinctly as in the 

 former species) ; the anterior angles are slightly prominent and de- 

 pressed ; the sides marginate and parallel ; at the base is a narrow 

 and well-defined channel, terminated (by being deflected at right 

 angles to the line of the base) before it reaches the lateral margi- 

 nation; the surface impunctate and flavous. Scutellum tolerably 

 large, triangular, impunctate, black. Elytra somewhat broader than 

 the thorax, parallel, slightly depressed, rounded at the apex ; punc- 

 tate-striate, the punctures being distinct and frequent, the stride 

 shallow ; near the scutellary angles the surface is impunctate, and 

 slightly raised, in a subcircular form : black, with the anterior (ante- 

 medial) margins flavous. Antennae tolerably long, filiform, fuscous, 

 with the four basal joints ferruginous. Legs flavous throughout, 

 the tarsi and the apical part of the tibiae being fuscous-black. 



Several males of this species (I have never seen the female) were 

 taken by Mr. Gray and myself at Petropolis in February 1857. 



