66 Memoirs on the Coleoptera 



Group II 



Subgenus Melanolia nov. 



This group is composed of a large number of species, singularly 

 constant in their oval or sometimes feebly rhomboidal and very 

 convex form and deep black, polished surface throughout, there 

 being absolutely no diversity in coloration. As in the preceding, 

 the elytra are only very slightly wider than the prothorax, with 

 much more feebly marked humeri than in any Diorymerus. The 

 abdominal characters are of the same nature as in Hiotus proper. 

 The species now in my collection are as follows : 



Discal elytral striae fine and very feeble or obsolete, the sutural distinct 2 



Discal striae distinct, though not subsulcate 13 



Discal striae coarse and very deeply grooved or sulciform; prothorax punctured 



throughout 14 



2 — Pronotum impunctate 3 



Pronotum punctured sparsely but conspicuously at the sides or apex n 



3 — Ninth and tenth elytral striae rather coarse and distinct throughout the length; 

 hind tibiae obliquely truncate and more or less conspicuously dentate ex- 

 ternally near the base 4 



Ninth and tenth striae very fine and indistinct, at least basally 8 



4 — Scutellum wider than long, very distinct, not closely fitting a thoracic sinus. . .5 



Scutellum very small, quadrate, not closely fitted 6 



Scutellum narrow, parallel, longer than wide, closely filling a small thoracic 



sinus 7 



5 — Form stout, ovoidal, extremely convex as usual, polished; beak rather thick, 

 feebly arcuate, compressed, two-thirds as long as the prothorax, not coarsely 

 but closely, rugosely punctate, almost as much so above, where there is a 

 fine and shining, subelevated median line; antennae medial, the oval club 

 three-fifths as long as the funicle; prothorax in profile very evenly and 

 moderately arcuate, also very strongly sloping from base to apex; prothorax 

 a fifth wider than long, the sides strongly converging and evenly, moderately 

 arcuate from base to the feebly subtubulate apex, distinctly more than a 

 third as wide as the base; surface very smooth; basal lobe broadly, evenly 

 rounded, with an extremely faint medial sinus at apex, the lateral impres- 

 sions obsolescent; scutellum flat and transversely suboval, finely, sparsely 

 punctulate; elytra somewhat elongate, at the broadly rounded humeri only 

 a little wider than the prothorax; sides subevenly, distinctly arcuate and 

 converging to the rather narrowly rounded apex, the striae, with exceptions 

 noted, and also the minute remote punctures, barely traceable; mes-epimera 

 with rather coarse sparse punctures throughout, the thoracic, flanks very 

 smooth; femora with strong, evenly and distinctly separated punctures, the 

 external tibial tooth large and very sharp; swollen and strongly sculptured 

 basal segment of the abdomen concave and setulose at the middle. Length 

 3.6 mm.; width 2.6 mm. Brazil (Chapada). November. A single speci- 

 men evanescens n. sp. 



Form slightly less obese and more rhombic-oval, the converging sides of the 

 elytra much less arcuate, the tip similarly rounded; beak nearly similar, 

 but a trifle longer and not quite so thick, the antennae almost similar; 

 prothorax differing only in being a little shorter, about a fourth wider than 

 long, the base similar, but with the lobe more narrowly and deeply sinuate 



