224 MEMOIRS ON THE COLEOPTERA 



Front not tuberculate but with an even transverse ridge; clypeus truncate 

 at apex, the post-apical carina straight and even, not bilobed; male 

 with the anterior tibiae unisinuate externally, tridentate in the 

 female; body smaller in size and differing sexually in form, oblong 

 or pyriform ( 9 ) ................................ Group 1 1 



The second of these groups occurs only in the tropical regions of 

 Mexico, where it replaces the more northern typical Orizabus. 



Group I. 

 Subgenus Orizabus in sp. 



The type of this group is the generic type Orizabus cultripes 

 Fairm., of which I have only a single female; it is distinguished 

 from any of those described below by having the basal bead of the 

 pronotum obsolete, though sometimes feebly traceable in the sub- 

 lateral impressions of the basal margin; otherwise it harmonizes 

 very well with more northern species of the snowi type. In all of 

 the species here defined the basal bead is entire and well developed. 

 The anterior tibiae of the female, in recently emerged examples, are 

 very strongly tridentate externally, the apex somewhat less obtuse 

 than in Aphonus and Psetidaphonus and the last tooth rather more 

 oblique, but through wear, the tibiae frequently assume such a 

 shape that it is difficult to trace their original outline even approxi- 

 mately. The species may be defined as follows: 



Apical pronotal impression (d 71 ) very large arid deep, extending laterally 

 through about half the entire width and longitudinally through 

 half the length. Body very large and stout, oblong, subparallel, 

 convex, shining, dark castaneous to black above, bright and pale 

 red-brown beneath; head (c?) between a third and fourth as wide 

 as the prothorax, coarsely and densely punctato-rugose, broadly 

 impressed transversely between the eyes, the tubercle strong and 

 abrupt, with two fine raised lines extending outward obliquely from 

 its base; trapezoidal clypeus more than twice as wide as long, the 

 straight sides abruptly and strongly lamellately elevated, the high 

 subapical carina strongly bilobed; antennal club a little shorter 

 than the stem; prothorax three-fifths wider than long, the sides 

 rounded and converging anteriorly in about apical, straighter and 

 feebly convergent posteriorly in about basal, half, slightly sinuate 

 near the base, the basal angles moderately rounded, the median lobe 

 broad, the beading strong and entire; punctures coarse and close-set 

 anteriorly, more asperulate in the oval depression, coarser and very 

 confluent toward the apical angles and, to a less extent and deeper, 

 posteriorly toward the sides, elsewhere finer, becoming obsolete 

 medially; apical tubercle very high and abrupt; scutellum rather 



