COLKOPTERA. 96 



all or but slightly compressed, and annulated transversely; the body 

 is almost cylindrical*. 



Hylesinus, Fab. 



Where the club of the antennae is also terminated in a solid club, 

 but slig-htly or not at all compressed, and annulated transversely, but 

 tapering to a point. The body is almost ovoid |. 



In the two following subgenera this club is still solid, but strongly 

 compressed; its inferior joints form concentric curves. In 



ScoLYTUs, Geoff. — Hylksinus, Fab. — Eccoptogaster, Herbst. 

 Gyllenh., 



Or Scolytus properly so called, the antennae are straight, beardless, 

 and inserted close to the inner margin of the eyes, which are narrow, 

 elongated, and vertical]:. 



Camptocerus, Dej. — Hylesinus, Fab. 



Where the antennae of the males are strongly geniculate and fur- 

 nished exteriorly with long hairs or threads; they are inserted at a 

 considerable distance from the eyes, which are elliptical and ob- 

 lique §. 



Ploiotrieus, Lat. — Hylesinus, Fab. 



The Ploiotribi are removed from all the other Insects of this family 

 by the club of their antennae, which is composed of three elongated 

 leaflets ||. 



Sometimes all the joints^ of the tarsi are entire, and the club of the 

 antenna;, always solid and compressed, commences at the sixth or 

 seventh joint. In 



ToMicus, Lat. — Ips, De Geer, — Bostrichus, Fab., 

 The antennae are not susceptible of being folded under the eyes, 

 and their club is distinctly annulated. The head is rounded above, 

 and almost glubuiar**. 



There is an cmargination of the side of the thorax. The tibiae are 

 not striated. The tarsi, at most, are as long as the latter, with the 

 first joint but slightly elongated. The body is cylindrical, and the 

 eyes are elongated and somewhat emarginated ff . 



* Lat., Gener. Crust, et Insect., II, p. 274; GylL, Insect., Suec, IV, p. 618. 

 t Lat., lb., p. 279. 



♦ Lat., lb., p. 278; Gyll., Insect. Suec, III, p. 215, and IV, p. 279. 

 § Hylesinus aneipennis, Fab. 



II Lat., lb., p. 280. 



^ They appear to be five in number; the penultimate is very small. The two 

 posterior legs are very remote from the preceding ones, and the body is cylindrical 

 or linear. The antennte are very short. 



** Broadly trilobate behind. According to M. Dafour their chylific ventricle, which 

 forms two thirds of the whole length of the alimentary canal, is covered with papillae, 

 while that of the Bostrichi is perfectly smooth. The same naturalist has observed 

 worms, resembling Ascarides, in the intestinal canal of the former, as well as in that 

 of various other Coleoptera. 



tt Lat., Gener. Crust, et Insect., II, p. 276. 



