DESCRIPTIONS OF NEW SrECIES. 1 3 



Cape San Lucas, Lower California: Mr. Xantus. The third 

 joint of the an tenure is one-half longer than the fourth, as in 0. 

 cumatilis, from which this species differs by the form of the thorax 

 and by the color. 



OODES Bon. 



41. O. fluvialis. Elongato-ovalis, niger nitidus, thorace latitudine 

 paulo breviore, ante medium fortiter angustato, lateribus magis rotun- 

 datis, angulis posticis subrectis, elytris latitudine sesqui lODgioribus, 

 convexis, striis punctulatis, interstitiis planis, 3io bipuuctato, metasterno 

 sat dense punctate Long. '50 ; lat. *20. 



Canada and Western States. Much narrower and more convex 

 than 0. americanus, with the sides of the thorax almost parallel 

 behind, converging only in front of the middle. The sculpture 

 beneath is just as in 0. americanus. A specimen from Canada is 

 still narrower and more convex, but as there are evidences of dis- 

 tortion about the specimen I consider the difference as accidental. 



Mr. Benj. D. Walsh informs me that this species is found quite 

 frequently in the sloughs of the Mississippi River, near Rock 

 Island, swimming freely in the water. 



42. O. texanus. Elongato-ovalis, nigro-seneus, nitidus, tborace latitu- 

 dine baud breviore, fere a basi antrorsum fortiter angustato, lateribus 

 modice rotundatis, elytris latitudine haud sesqui longioribus, striis 

 punctatis, 7ma obliterata, interstitio tertio bipunctato, metasterno abdo- 

 minisque basi rude punctatis. Long. -45 ; lat. '18. 



Texas: Mr. S. B. Buckley. Narrower and flatter than 0. 14- 

 striatus, with the striae of the elytra finer and quite distinctly 

 punctured. 



CRATOG1VATHIS Dej. 



43. C. alternating Piceus nitidus, tborace capite paulo latiore, 

 latitudine fere sesqui breviore, subcordato postice angustato. lateribus 

 rotundatis setigeris postice subsinuatis, angulis posticis rectis, basi 

 utrinque foveato, elytris convexis, striis profundis, interstitiis lmo 3io 

 5to 7mo et 9no punctis setigeris parcis fere uniseriatini digestis, anteii- 

 nis, labro, palpis pedibusque rufo-testaceis. Long. -42. 



Arkansas ; Mr. Ulke. In C. setosus all the intervals of the 

 elytra are furnished with setigerous punctures ; in C. cordaius 

 they are all without punctures. 



