614 Mr. J. O. Westwood on the Paiissidce, 



of Scolytus, Cossonus, and other curculionideous genera), I do 

 not think that any natural affinity exists, either regarding struc- 

 ture or habits : neither do I consider that any material affinity 

 exists between them and the Mycetophagidce*. On the other 

 hand, in general appearance, in the consistency of their external 

 structure, and probably also in their natural habits, they make the 

 nearest approach to the Trogositarii'^: but the trophi are very dis- 

 similar, and the antennae oi Pentaplatarthrus and Cerapterus pre- 

 sent no appearance of a terminal clava ; which clearly shows the 

 great hiatus existing between these insects and the Trogositarii, 

 and appears to point the way to the Cuctijidce (the remaining 

 family placed by Latreille between the CurcuUonidce and the 

 Cerambi/cida), and which may perhaps hence be considered as 

 having the greatest affinity with the Paussidce, particularly when 

 we also notice the depressed bodies, the formation of the antennae, 



and 



* The genera composing the section MycetopJiages, as restricted by Latreille in the 

 liew edition of the Regne Animal, (with the exception of Colydium, which is placed 

 alone in a distinct subdivision,) appear to agree more nearly in natural affinity than 

 those of which the section is composed in any of his previous works, at least so far as 

 I am able to judge from the genera which I have dissected : — they are Mycelophagus, 

 Triphyllus, Meryx, Dasycerus, Latridius, and Silvanus. The situation of the last 

 appears to me, however, doubtful, Mr. Curtis has also proved the intimate affinity 

 between Tetratoma and Mycetopkagus. 



f This family appears to me to be capable of demarcation, from the general appear- 

 ance of the species, and from the structure of their trophi, especially the lower lip ; — 

 in my opinion, founded upon the formation of the latter organs in many of these in- 

 sects which I have dissected, it naturally includes the genera Trogosita, Megagriathus, 

 Cerylon, Rhyzophagus, Nemosoma, Colydium, Monotonia, Bitoma, Cicones, Synchita, 

 and probably Lyctus. To these groups must also be added the pentamerous genus Ips, 

 which has recently been ably illustrated by Mr. Curtis, who however, taking Latreille 

 for his guide, has placed the genus in the family NitiduHdtE, and merely stated the chief 

 diflferences existing between it and Nitidula, thus evidently regarded as the genus most 

 nearly allied to Ips. It is impossible, however, on examining the Ips J'errugineus, 

 (which Mr. Curtis has considered the type of the genus,) not to be struck with its 

 resemblance to some of the preceding genera, such as Cerylon, Nemosoma, Sfc, which 



resemblance 



