TRIMEROUS FUNGUS-BEETLES. 
179 
these tribes, their separation, probably, would never have taken place, 
since, as we have seen, the number of these joints is subject to much 
variation in the smaller species of Clavicornes. But a much more im- 
portant distinctive character is the structure of the tarsal joints ; being 
dilated, evenly cushioned beneath, and with the penultimate joint often 
deeply bilobed, thus allying them to the Phytophaga, whilst it sepa- 
rates them from the pentainerous Clavicornes, which, though they usu- 
ally have the tarsi more or less garnished with hairs, never, we believe, 
exhibit the dense and even brush of hair-like papillae which is so char- 
acteristic of the genuine Tetramera; and in the few instances in which 
any dilatation of the tarsi occurs among the Clavicornes, it is small in 
extent and limited to the anterior feet of the males, being a sexual dis- 
tinction. It is also worthy of note that the important and rudiinental 
joints in the present tribe are uniformly the penultimate, as in thetetra- 
merous section, whilst in the imperfectly developed tarsi of the small 
pentamera, it is usually the first, or first and second joints that are de 
ficient. 
The characters of the few known larvae of this tribe do not afford any 
clear indications of their systematic position ; for whilst the larva first 
described by Fischer and copied by Westwood, and supposed to be that 
of Tritoma, strikingly resembles the larvae of the Chrysomelidae in its 
thick fleshy and spotted body, the larva of Triplax, figured by the last 
named author, bears, as he remarks, a strong resemblance to that of the 
genus Colydium, which we have placed in our aberrant group of Sub- 
clavicornes ; and the. larvae of Endomychus have beeu compared both 
to those of Silpha and Lampyris. Thus it appears that the position ot 
these families, separate and remote from the pentainerous Clavicornes, 
first assigned to them by Latreille, rests upon strong considerations ; 
and we may add that Lacordaire, one of the latest and highest author- 
ities upon the classification of this order, has virtually given his sanc- 
tion to this arrangement. For though his work had not reached the 
trimerous section, at the time of his death, it is evident, from his not 
including them iu the pentamerous series, that he had reserved them 
for this position. 
It is worthy of remark that the dilated and cushioned tarsi of these 
insects would seem to indicate a decided diversity of habit as compared 
with other fungus beetles which have simple tarsi. The most obvious 
explanation is that this structure of the feet enables them to adhere to 
the smooth surface of the boleti upon which they deposit their eggs and 
in which their larvae reside, whilst those beetles which subsist mostly 
upon the fungi which grow beneath the bark ot decaying trees, require 
no such provision. 
