374 INSECT A. 



rather in the form of a reversed cone than cylindrical, and finally, 

 in which the mentum is slightly emarginated, will re-enter the sub- 

 genus 



HisTER, properly so called. 



Some species in which, as in the Hololeptae, the four posterior 

 tibiae have but a single range of small spines, and that also live under 

 the bark of trees, constitute the genera Platysoma and Dexdrophi- 

 Lus of Leach. The first(l) only differs from the second(2) in the 

 flattening of the body above, and in the shortening of the thorax, 

 which is also narrowed anteriorly. A species of the same division, 

 11. proboscideus, Payk., Monog., VIII, 4, has a peculiar form. The 

 body is long and narrow, and the thorax more than half as long again 

 as it is wide. 



The remaining Histeroides have two ranges of spines on the four 

 posterior tibiae. They are the only ones which Dr Leach retains in 

 the genus Hister. 



//. unicolor, L. ; Payk., lb., II, 7. Four lines in length; en- 

 tirely black and glossy; three dentations on the exterior side of 

 the two first tibiae; two striae on each side of the thorax, and four 

 on the external part of each elytron, that nearest the margin in- 

 terrupted. Very common. 

 The number of tibial dentations, that of the strix on the thorax 

 and elytra, their punctures, and the form of the body, have furnished 

 M. Paykull with excellent characters, by means of which he has 

 well described the species. 



A last subdivision of this tribe comprises very small Histeroides, 

 with a thick and almost globular body, of which the but slightly or 

 not at all laterally compressed praesternum does not advance over the 

 mouth, and is straight in front. 



In some — Abr^eus, Leach — it is prolonged to the anterior angles 

 of the thorax, and entirely covers the antennae when they are con- 

 tracted; in the others — Onthophilus, Leach — it is narrower; but 

 here the antennal club is received into a very distinct orbicular 

 cavity, situated under the anterior angle of the thorax. The ante- 

 rior tibiae are frequently narrow, almost linear, and edentated. The 

 last superior semi-segment of the abdomen is curved inferiorly, and 

 appears to terminate il(3). 



(1) Ulster picipes, Fab. ; Payk., lb., VllI, 5; — H. Jiavicornis, Id., VIII, 6; — H. ob- 

 longus, Id., X, 3. 



(2) A.pundatus, Id. VII, 5. 



(3) The H. globosus, Payk., VIII, 2, is referred by Leach to his ^enus Abrasus, 

 and also the H. minutus, Id., VIII, 1; to his Onthophilus, he refers the Hixt. 



