614 Mr. J. O. Westwood on the Paussidce, 
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 of 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 Cucujidce (the remaining 
family placed by Latreille between the Curculionida and the 
Cerambycidce), 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 Mycetophages, as restricted by Latreille in the 
new edition of the Regne Animat, (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, 
Triphyl/us, Meryx, Dasycerus, Lalridius, and Silvanus. The situation of the last 
appears to me, however, doubtful. Mr. Curtis has also proved the intimate affinity 
between Tetratoma and Mycelophagus. 
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, Rliyzophagus, 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 Nitidu/idce, and merely stated the chief 
differences existing between it and Nitidula, thus evidently regarded as the genus most 
nearly allied to Ips. It is impossible, however, on examining the Ips Jerrugineus, 
(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 
