272 MEMOIRS ON THE COLEOPTERA 



in Megasoma and many other genera. The four species before me 

 may be known as follows : 



Prothorax widest behind the middle. Body oval, convex, shining, deep 

 black throughout, the bristles at the sides of the prothorax beneath, 

 on the legs and post-coxal prosternal process, obscure fulvous; head 

 small, very short, barely two-fifths as wide as the prothorax, coarsely, 

 subconfluently punctate, the ridge obtuse on its summit, scarcely 

 at all depressed medially and but little over a third as long as the 

 entire width; clypeus very short, feebly impressed along the middle, 

 the acute apical tubercle strongly elevated, the sides below the 

 true lateral edges much expanded; prothorax two-fifths wider than 

 long, the sides evenly and moderately arcuate, converging anteriorly 

 from well behind the middle; apex two-thirds as wide as the base, 

 the sinus transverse, the angles acute, anteriorly prominent; side 

 margins fine, the entire basal bead defined by a coarse deep even 

 groove; surface very feebly impressed along the median line behind 

 the middle, the punctures coarse, dense, deep and close-set but not 

 confluent antero-laterad, elsewhere rather coarse but well separated, 

 sparser and still smaller medio-basally; scutellum very small, having 

 a few punctures; elytra barely longer than wide, evenly rounded in 

 posterior half, rather wider than the prothorax and two-thirds longer, 

 the striae regular and coarsely punctate, not deeply impressed, the 

 intervals with extremely minute sparse punctulation; pygidium of 

 the female with the exposed apical part rather coarsely but sparsely 

 punctate and nearly flat; abdomen sparsely, rather coarsely punc- 

 tured toward the sides; anterior tibiae purely tridentate as usual in 

 the genus, the hind tibiae expanded, even throughout, with short 

 stout obtuse spinules at apex and with two oblique feeble ridges at the 

 middle, neither at all spiniform externally. Length (9 ) 15.5 mm.; 

 width 8.0 mm. Mexico (Saltillo, Coahuila), Wickham. 



*brevis n. sp. 



Prothorax widest at the middle, the sides parallel, evenly and rather 

 strongly arcuate 2 



2 Body oblong, the elytra distinctly longer than wide. Upper surface 

 not quite so convex, dull black, though possibly from wear in the 

 unique type, black beneath; head larger than in brevis, three-sevenths 

 as wide as the prothorax, coarsely punctured, very sparsely medio- 

 basally, the very short clypeus rather finely and closely punctato- 

 rugulose, the ridge rather fine and feebly bilobed along the summit, 

 nearly two-thirds the total width, gradually evanescent at the ends; 

 clypeal apex as in brevis; eye-canthus large, rounded, much more 

 prominent than the eye; prothorax large, convex, not quite one-half 

 wider than long, transversely oval, the very feebly impressed median 

 line basally, punctures and beading nearly as in brevis, but with the 

 punctures finer, more remote and more obsolete basally throughout 

 the width; scutellum very small, with rather close-set punctures 

 except posteriorly; elytra a fifth longer than wide, barely as wide as 

 the prothorax, rounded in apical two-fifths, the striae coarse but only 

 very feebly impressed, the punctures rather coarse, well impressed and 



