— 30— 



uietathorax be'uvj, distinctly though slightly wider in liont, and giadualU 

 narrowed behind. 'Jlie femora are not spinose and the spines of the an- 

 tenna,- are never long. The antenna; are longer than the body in (^, 

 the prothorax is very densel\- punctured with a posterior medial channel 

 and liorsal cicatrices. In 9 ^^^ antenna; are shorter and the prothorax 

 coarsely punctured with a medial and two dorsal callosities. The species 

 are separated as follows: 



Uody uniformly finely pubesceiii ; 



Buih angles uf 3cl and 4ih joint of aniennut; spinose procerum. 



CJuier angles only sp.iiose simplicicoUe. 



Body irregularly pubisct-nt, with spots of coar.ser and denser hnii ; 



Pubescence molt led irregular atomarium. 



I'ubisccnce uniform, fulvous rufulum. 



Spar,-.e!y pubescent, elytra very coarsely punctured before ihe middle, with an ine 

 gular transverse patch ol white pub.'scence at the middle taeniatum. 



R. procerum Ixc. I'roc. Ae. Phil. 1859, p. 88. 



Length 37.5 mm. = 1.5 inch. Hab. New Mexico, Cal. 



R. simplicicoUe Hald. Proc. Ac. Phil. IIJ, p. 151; Lcc. Juurn. Acad. Nat. 

 .Sei. Phil, ser, 2, II, p. 12; palverulentu.s Hald. Trans. Am. Phil. Soc. X, p. 32; Leconiei 

 Dej. Cat. 3d ed. p. 352; Chev. Jouin. of Ent. 1, p. 243. 



Length 44 mm. = 1.75 inch. Hab. United States. 

 The two species above mentioned are very close, and separable only 

 bv characters given in the table. The species of this and the succeeding 

 genus are founded on structural differences, in which the family Cetam- 

 bycidae is so rich. In the present and in other instances these differences 

 are so slight as to indicate that the species arc either of very recent ori- 

 gin or are now tending to coalesce. We fail however to find i ntergrades 

 which would justify us in uniting the species and merely caution the 

 student that the table must be followed very literally to correctly identify 

 specimens, i?. aperarium. White, = one of the above species. 



Since the above was in type, Dr. Horn writes as follows: "Alter 

 examining my series, I can not separate procerum and simplicuolk. and 

 would advise their union under the former name. The arrangement of 

 the antennal spines is an illusory and evanescent character." 



R. atomariuin Drury, 111. II, 1773, Ind. 1, p. 93. t. 41, f. 6; I^c. J. A. P. ser. 2, 

 II, p. 177; mwylandicus Fab. Syst. Ent. p. 179; Uliv. Ent. IV, 70, p. 6, t. i, f. 5; 

 nodticolc/r L. ed. Gmel. I. 4, p. iS^y ; pulvei-ulentus De G. Ins. V, p. 118, t. 14, f. 12. 



Ixingth 22- 31 mm. = .88—1.22 inch. Hab. Middle and Southern Slates. 



R. rufulum Hald. Trans. Am. Phil. X, p. 32. 



l.ength 22 — 28 mm. = .88— 1. 15 inch. Hab. Middle States. 



These are again closely related. The fulvous color will distinguish 

 rufulum as well as the uniform pubescence: atomarium being darker in 

 every specimen we have seen. 



