COLEOPTERA. 527 



or pectinated, and where the posterior extremity of the presternum 

 offers no emargination(l). 



Megaderus, Dej. Ccdlidium, Fab. 



Where the antennae are simple, and shorter than the body, and 

 the posterior extremity of the praesternum is emarginated, and re- 

 ceives, in that emargination, the opposite end of the mesosternum, 

 so that they are intimately united or seem to form but one plane(2). 



Those, in which the thorax is very uneven, tuberculous, or pluri- 

 dentated, with the prsesternum carinated or terminated posteriorly 

 in a point, have been arranged in four subgenera. 



Here the antennae are long, setaceous and simple, or at most 

 slightly spinous or furnished with fasciculi of hairs. 



The thorax is always large, very uneven, and hardly wider than it 

 is long. 



Dorcacerus, Dej. Cerambyx, Oliv. 



The species of this subgenus are distinguished from all the others 

 by their large vertical head, which is almost as wide as the thorax 

 taken in its greatest transversal diameter, and plain and densely pilose 

 before. The antennae are very remote. The prsesternum is not 

 raised into a carina, and terminates simply in a point. The scutel- 

 lum is small(S). 



Trachyderes, Dalm. Cerambyx, Fab. 



Where the thorax is large, much wider than the head, and the pos- 

 terior (and frequently the opposite) extremity of the praesternum is 

 raised into a carina; where the scutellum is elongated, the elytra 

 are widest at base, and become narrower as they progress towards 

 the extremity; and where the antennae are not furnished with fasci- 

 culi of hairs(4). 



Lophonocerus, Lat. 



Where the head is also narrower than the thorax, and the poste- 

 rior extremity of the praesternum is carinated; but this thorax, as 

 well as the scutellum, is proportionally smaller. The elytra are 

 widened towards their extremity, or at least do not become narrower;. 



(1) See Schrenh., Synon. Insect; Dalman, Anal. Entom. ; and Germar, Insect, 

 Spec. Nov. 



(2) Callldium stigma, Fab.; Dej., Catal., p. 106. 



(3) Cerambyx barbatus, Oliv.; Dej., Ibid., p. 105. 



(4) Schoenherr, Synon. Insect., I, 3, p. 364. 



