COLEOPTERA. 469 



along the side of the scutellum in the manner of an angle. Such is 

 the 



Epitragus, Lat.(l) 



In the others the mentum does not cover the base of the maxillae, 

 and the posterior margin of the thorax is straight, or but slightly 

 dilated behind. 



Cnodalon, Lat. 



Where, from the fifth joint, the antennae are strongly compressed 

 and serrated, and where the head is much narrower than the tho- 



rax(2). 



Campsia, Lepel, and Serv. — Camaria, Id, 



Where the antennae, from the sixth joint, are slightly serrated, 

 and the head is as wide as the posterior margin of the thorax. The 

 body is proportionally longer and less convex, and the thorax wider 

 posteriorly(3). 



In all the other Helopii, the mesosternum presents no remarkable 

 emargination, and the posterior extremity of the praesternum is not 

 extended into a point. 



Here the body is sometimes ovoid or oval, and at others more 

 oblong but narrowed at both ends; it is never cylindrical or linear, 

 nor much flattened. Certain subgenera have been formed with He- 

 lopii, which approach the first in their strongly inflated body, which 

 is gibbous posteriorly. 



Those, in which the body is almost ovoid or short, and the thorax 

 transversal, plane or simply curved, compose the following sub- 

 genera. 



Spheniscus, Kirby. 

 Easily mistaken at the first glance for Erotylus, and in which, as 



(1) Lat., Gener. Crust, et Insect., II, p. 183, and I, x, 1. The maxillae are un- 

 guiculated like those of Melasoma. This subgenus, and the two following subge- 

 nera are peculiar to South America. 



(2) Lat., Gener. Crust, et Insect., II, p. 182, and I, x, 7. 



(3) Encyc. Method., article Sphenisque. Messrs Lepeletier and Serville give 

 but ten joints to the antennse of the Camarias. a character which would distinguish 

 them from the other Helopii: but we have distinctly seen eleven in various Helo- 

 pii from Brazil, which appear to us closely allied to the C. niiida, quoted by them. 

 Until we can verify this anomaly in the individuals examined by those gentlemen, 

 we think it best to unite the two subgenera. Besides the Cnodalon irroratum of 

 Germar, quoted in this article, refer the Ihxicum geniculutum and nigripes, ejusd., 

 to the same subgenus. 



