DESCRIPTION OF GENERA AND SPECIES- 



OMUS Esch. 



0. Dejeanii, aeneo-ater, opacus, thorace latitudine breviore, trapezoides, depresso, profunde 

 intricato-rugoso, ad apicem striato, elytris punctatis subrugosis, foveisque profundis irregulariter 

 impressis. Long. *7 8. Tab. I, Fig. 1. 



Reiche, Annales de la Soc. Entom. France, 7,297 ; Tab. 10, Fig. 1. 



Fort Vancouver, Dr. J. G. Cooper ; Steilacoom, Dr. Suckley. 



0. californicus, ater subopacus, thorace latitudine baud breviore, trapezoides, modice 

 convexo, profundissime intricato-rugoso, elytris profunde punctatis, punctis vix inaequalibus. 

 Long. -6. Tab. I, Fig. 3. 



Eschscboltz, Zool. Atlas, 5, 4 ; Tab. 4, Fig. 1 : Reiche, Ann. Ent. Soc. Fr. 7,301 ; Tab. 

 10, Fig. 3. (copied) : Mann. Bull. Mosc. 1843, 182. 



San Francisco ; found by me in February, floating in pools of water ; a female was liberally 

 presented to me by Mr. J. Ph. Wild. 



0. Audouinii, ater, subopacus, thorace latitudine non breviore, trapezoides, modice convexo, 

 intricato-rugoso, minus profunde in disco, margine apical i sublaevi, elytris subrugosis, 

 punctatis, punctisque maioribus dispersis impressis. Long. 55 7. Tab. I, Fig. 2. 



Reiche, Annales de la Soc. Entom. France, 7,297 ; Tab. 10, Fig. 2. 



Oregon, at Fort Vancouver, Dr. Cooper. Only males were procured, but for a female, col 

 lected by the late J. K. Townsend, M.D., I am indebted to Dr. T. W. Harris. 



These three species, the only ones known, form two natural divisions, according as the 

 thorax is short and depressed, (0. Dejeanii,) or oblong and moderately convex. The two 

 species of the latter division resemble each other closely in form, size, and sculpture, the less 

 deeply rugous thorax of 0. Audouinii at once distinguishes it ; the head of that species is also 

 less deeply rugous between the eyes than in 0. californicus ; the elytra are more distinctly 

 rugous, and there is an obvious difference in the size of the punctures of the elytra ; on close 

 inspection, a similar character may be seen in 0. californicus, but much less distinctly. 



PRISTODACTTLA Dej. 



P. lenis, piceo-nigra, subnitida, thorace subquadrato, postice paulo angustiore, lateribus 

 rotundatis margine subreflexo, angulis posticis obtusis rotundatis, ad basin utrinque late 

 foveato, elytris thorace latioribus, tenuiter striatis, bipunctatis, antennis pedibusque rufo- 

 piceis ; unguibus ad basin paulo serratis. Long. 44. 



Anchomenus lenis Mann. Bull. Mosc. 1853. 



Kadjak, Russian America ; Baron Chaudoir. This species is closely allied to P. advena Lee., 

 but is larger. The thorax is more narrowed behind, and the sides are less broadly reflexed. 

 I was much surprised to find the ungues of this species finely serrate from the middle to the 



