50 GEO. II. HORN, M. D. 



transverse ridire on the vertex, slightly sinuate on top. The thorax 

 of the female has in front an elevated ridge. The male has in addi- 

 tion a deep fossa below each end of the ridge, bounded exteriorly by 

 an acute elevation. The ends of the ridge are also elevated into an 

 acute tooth-like process. After a very careful study of many speci- 

 mens I cannot but consider as one species, the two forms about to be 

 described. 



Two varieties may be distinguished in this species : — 



a. — tumcfactus, Beauv. — Elytra with seven strice between the suture and hu- 

 merus. 



b. — farctus, Fab. — Elytra with five strife only. 



The less number in the latter form is caused by a partial or total 

 obliteration of the 2nd and fifth stride. The autennal club in both 

 forms is broadly oval or round. 



This species is as widely difi'used as the preceding, and is similar 

 in length, being, however, broader and more convex.' 



ODONT.EUS, Klug. 



This genus may be readily known from the preceding by having 

 the eye entirely divided by a narrow process of the anterior canthus. 



Three species are known from the United States. 

 0. filioornis, Say {Bolboc.) Journ. Acad. 3, 211. 



Pale castaneous or ferruginous in color, shining. The male has 

 the horn movable as in the European species. Length .34 inch; 

 8.5 mm. 



Middle and Central States. 

 0. cornigerus, Mels. {Bolboc), Proc. Acad. II, 138. 



Similar in color to the preceding, but occasionally black. The 

 horn is less slender than in Jiliconiis and fixed. This species attains 

 a somewhat larger size than the preceding and is usually more robust. 



Middle and Central States. 

 0. obesus, Lee. Proc. Acad. 18:39, 282. 



Of this species both sexes are now known. It is larger, more robust, 

 with the elytral strioo less deep and closely punctured. The base of 

 the thorax is much less sinuate than in either of the preceding species, 

 and the hind thoracic angles are rectangular. The sides are gradu- 

 ally narrower from base to apex and rather feebly rounded. The 

 male is rather smaller than the female and differs from the male of 

 cornigerus by a less densely punctured thorax, with regularly but feeb- 

 ly rounded sides. The processes from the upper surface on each side 

 are acute at apex. Frontal horn fixed. Length .44 inch; 11 mm. 



Occurs at Table Mountain, south of San Francisco, Cal. 



