38 Memoirs on the Coleoptera 



17 — Fourth tarsal joint with the outer lobe a little longer than the 

 inner 18 



Fourth joint symmetric, feebly emarginate 19 



18 — Upper surface blackish-piceous, the elytra black, broadly reflexed 

 thoracic margins diaphanously pale; legs and entire antennae and 

 palpi pale testaceous; surface moderately convex; head rhomboidal, 

 slightly elongate, with narrowed neck and very prominent though 

 moderate eyes, four-fifths as wide as the prothorax, the anterior 

 impressions broad, the surface strigilate externally; antennae very 

 slender, rather more than half as long as the body; prothorax but 

 slightly wider than long, the sides subprominently rounded before 

 the middle, very broadly and feebly sinuate posteriorly, the tips of 

 the obtuse angles distinct though not very sharp; base arcuate at 

 the sides, scarcely as wide as the apex, which is sinuate, with rounded 

 angles; surface with some transverse rugulae, the impressions feeble; 

 foveae large, deep, nearly smooth, traceable anteriorly beyond the 

 middle, gradually merging into the broadly reflexed sides; elytra 

 long, fully three-fourths longer than wide, twice as wide as the 

 prothorax, the sides well reflexed and diaphanous, gradually ogival 

 behind, the sinus oblique and but little more than straight; striae 

 nearly smooth, impressed; intervals very moderately convex; 

 surface of each with a large feeble indentation near the apex; an- 

 terior tarsi very feebly dilated in the male. Length (cf' 9 ) 9-5~ 

 ii.o mm.; width 3.6-4.2 mm. Lake Superior (Bayfield and 

 Marquette), Iowa (Cedar Rapids) and Pennsylvania (Pittsburgh). 

 [Platynus marginatus Lee; Colpodes marginatus Chd.]. 



reflexus Lee. 



Upper surface more convex, without the posterior indentation on each 

 elytron, polished, black, the anterior parts slightly picescent, the 

 suture finely piceous; legs and entire antennae pale; head nearly 

 as in the preceding, the antennae not quite so long or so slender; 

 prothorax more quadrate, nearly as long as wide, parallel, with 

 more feebly and evenly arcuate sides, these being less broadly 

 reflexed, less diaphanous, not becoming sinuate toward the angles, 

 which are very obtuse, with the tips definable though blunt; base 

 strongly arcuate at the sides, as wide as the apex, which is rather 

 feebly sinuate, with obtuse and rounded angles; surface smooth, 

 the impressions nearly obsolete, the stria very fine; foveae large and 

 smooth, only very moderately impressed, not traceable beyond the 

 middle and there not near the sides; elytra nearly three-fourths 

 longer than wide, twice as wide as the prothorax, gradually rounded 

 at tip, the sinus long and extremely shallow; striae fine, smooth, 

 feebly impressed, the intervals very slightly convex, the three 

 punctures fine; basal margin feebly sinuate, forming an extremely 

 obtuse angle with the sides. Length (9 ) 9-5 mm.; width 3.6 mm. 

 Mexico (Tamaulipas). A single example *convexulus n. sp. 



19 — Elytra oblong-subelliptical and with the diaphanous side margins 

 as widely reflexed as those of the prothorax. Upper surface convex, 

 highly polished, blackish, the anterior parts rufescent, the thoracic 

 sides well reflexed and diaphanous; under surface and legs rufous, 



