CERAMBYCIDAE. 339 



the base. The antennae, except in Graphisurus, are excessively 

 long in both sexes, densely fringed beneath with soft hair in the 

 % , and occasionally with an apical dilatation on the inner side of 

 the 4th (A. nodosus), or 5th (A. spectabilis) joint. The 1st joint 

 of the hind tarsi is very long, and the last abdominal segment 

 of the 2 is prolonged into an ovipositor, nearly half as long as 

 the elytra. 



Antennae not much longer than the body; 



Pubescence mixed with erect hairs. GRAPnisuRirs. 



Antennae very long in both sexes ; pubescence not mixed with erect hairs ; 



Joints of antennae 3 — 11 equal in length. Acanthocincs. 



3d and 4th joints very long, 5 — 11 shorter than 4th. Edtessus. 



The last genus is founded on a very singular insect from Lower 

 California, of which only % specimens are before me. I infer from 

 the general appearance, and sexual characters, that the ? must 

 have a long ovipositor. The outline of the prothorax is straight 

 nearly to the base, as in Liopus, then armed with a short spine ; 

 the elytra are uneven with small elevations, as in certain Lepto- 

 stylns. I have named it Eu. granosus. 



Our species of Acanthocinus lead insensibly to Eutrypanus; 

 the two species of the "Western slope, Mdilis obliquus and spe- 

 tabilis have the sides of the elytra suddenly compressed and 

 declivous, with a distinct carina running from the humeri oblicmely 

 backwards ; the same thing is observed in a less degree in A. 

 nodosus, but very feebly in Lamia obsoleta Olivier, which is in- 

 correctly referred by Lacordaire to Graphisurus. 



Group IV. — Dectes. 

 A single genus, with one species in the Atlantic States and 

 one in Texas, constitutes this group. The form is elongate, and 

 cylindrical, the antenna? about one-fourth longer than the body, 

 scape very long, cylindrical, outer joints diminishing slightly in 

 length. The lateral spine of the prothorax is acute, and slender, 

 placed near the base, directed obliquely and horizontally outwards. 

 The elytra are slightly truncate at tip, not wider than the pro- 

 thorax; the front coxal cavities are separated by the very narrow 

 presternum, which is not dilated behind ; they are closed very 

 narrowly, so that on superficial examination they seem to be 

 widely open, and were erroneously described as such by me ;* 



* Joum. Acad. Nat. Sci. Phila., 2d ser. ii. 144. 



