NORTH OF MEXICO. 



305 



Tooth of femur broad in % ; elytra sub-opaque and with distant series of large punctures; 



punctures distant from each other. seriata. 



Male unknown. Elytra striate, strise approximate and with very closely placed punctures, s t r i o 1 a t a . 



Pub-Genus ELEODKS. 



This division contains all the large species, and the smallest is scarcely below the me- 

 dium size. It may be distinguished from the other divisions by having the tarsi entirely 

 setose beneath, never silken or spongy pubescent. The first joint of the anterior tarsus 

 of the male is somewhat thickened in the first few species; this would never be mistaken 

 for the marked expansion and peculiar vestiture of the Promus group. The form of men- 

 turn' is also subject to some slight variation; tins will be alluded to under the species 

 themselves. 



Group I. is characterized by the marked inequality between the spurs of the anterior 

 tibia 1 , notably in the females, and in accordance with this variation we may again sub- 

 divide the group into two parts'. Section I. contains the large sulcate species. With 

 them the anterior spur of the anterior tibia is much smaller than the posterior, the latter 

 though scarcely longer is much broader and more robust and obtuse; at the tip. Here, 

 also, occurs the thickening of the first joint of the anterior tarsus of the male. 



C. obscura, Say, (Blaps) .Tourn. Acad. 8, 259. Am. Bnt. tab. Hi. (Eleodes) Esoh. 



I cannot accept the feeble differences between the five species described, as indicative 

 of specific distinction. With very large series it would be difficult indeed to define even 

 races. The three principal variations have been selected as centres, and may for conve- 

 nience be called "races," each may receive separate notice, and the student be thereby 

 the better enabled to determine either their validity as species, separation as races, or 

 complete union as mere varieties. 



dispersa, Lee; deleta, Leo. Proo. Acad. 1858, p. 1.82. 



Variations of sculpture alone form the differences between the three races. The mid- 

 dle lobe of the mentum is large, obtuse in front, coarsely punctured and elevated more or 

 less along the median line, the lateral lobes are small, strongly infiexed, scarcely evident 

 without careful examination. The head is often coarsely punctured, and the clypeo- 

 frontal suture by no means rarely visible. Thorax broader than long, moderately convex 

 and shining, and sparsely punctured, anteriorly truncate with obtuse angles. The sides 

 are rather broadly rounded in front, slightly sinuate behind, margin fine, slightly reflexed, 

 base feebly sinuate and one-fourth narrower than at the widest portion; the hind angles 

 are never acute, though distinct, generally rectangular. The elytra vary in shape even in 

 individuals of the same sex. Their form is, however, elongate oval, generally twice longer 

 than broad, sides more or less rounded, occasionally sub-parallel in some males. The 

 margin is never acute even at humerus, always rounded. The sculpture consists of very 



AME1U. PIIILOSO. SOO VOL. XIV.— 17 



