234 



chidce is deceptive, for although they are pentamcrous, yet the concealed joint is 

 the first, and not, as in the Bostrichidx, the fourth. This is also the case in some 

 genera of the Cleridae ; I, therefore, consider that the most natural situation of 

 Apate is between this family and the Anobia, notwithstanding their resemblance to 

 Bostrichus. This appears to be confirmed by the discovery by Professor Ratzeburg 

 (who, as he has informed me, was long struck by the remarkable similarity of the 

 holes bored by Apate and the Anobia) of the larva of Apate, which in contradistinc- 

 tion to the footless larvae of the Bostrichi, very much resembles those of the 

 Anobia. 



The Bostrichidx may be divided into three very natural groups, characterized 

 by the proportions of the head and thorax. In the first, the thorax is generally 

 narrowed anteriorly, and encompasses the posterior portion of the head, leaving, 

 however, the greater portion of it free, and for the reception of which there is a 

 more or less considerable concavity beneath in front of the anterior coxa?. The 

 head is anteriorly elongated into a short thick rostrum. In the second group the 

 globose head is wholly retractile within the thorax, which arches itself like a capu- 

 chin over it, forming a deep emargination, beneath which, however, it is always 

 even in the middle distinctly margined. The third group, lastly, which contains 

 but one genus, has the thorax neither emarginate nor impressed beneath, and a 

 free head frequently wider than the thorax. 



Group I. — Hylesines. 



Head exserted, the rostrum short, thick, and advanced. The antennae (ex- 

 cepting Phloeotribus ) inserted at the sides of the rostrum. Thorax beneath ante- 

 riorly emarginate, with an impression (often obsolete) for the reception of the head. 

 The third joint of the tarsus generally emarginate or bilobate. 



Genus I. — Hylastes, Erichs. The funiculus of the antennae seven -jointed; 

 the knob four-jointed, orbiculate, compressed ; the tibiae externally denticulated. 

 This genus contains, 1. Hylastes ater, Payk., which is the Hylesinus piniperda 

 of Fabricius, as the type, with nine other species. But it is further separated into 

 two divisions, viz. : — a. The mesosternum truncated anteriorly ; the third joint of 

 the tarsus cordate, not dilatated : and b. The mesosternum conical and prominent ; 

 the third joint of the tarsus dilatated and bilobate. 



Genus II. — Hylurgus, Latr. The funiculus of the antennae six-jointed, the 

 club quadriannulate, subglobose ; the tibiae externally denticulated. The only 

 known species is the H. ligniperda, Latr. 



Genus III. — Dendroctonus, Erichs. The funiculus of the antennae five- 

 jointed, the knob quadriannulate, suborbiculate and compressed. The tibiae exter- 

 nally denticulated. The type of this is the Bostr. micans of Kugelan, frequently 

 mistaken for the Hyles. ligniperda, Fab. ; besides which it contains, 2., Scol. 

 terebrans, Oliv., 3., Dermestes piniperda, Lin., and two others. 



