in the Tetramerous and Trimerous Coleoptera. 71 
his ** Coccinelle à 15 points noirs," although he considered the 
genus as trimerous*. And the fact is, that this truly tetra- 
merous structure prevails, as far as I have observed, throughout 
all-the insects hitherto called trimerous : for instance, in Eumor- 
phus immarginatus, a Sumatran insect, which I more particularly 
specify, for the same reason as the Javanese Coccinella, because 
they are both large species in a group of which the insects are 
generally small, and because the tetramerous structure of their 
tarsus is therefore visible to the naked eye. 
These very remarkable facts destroy even the very nomencla- 
ture of M. Latreille’s system, and throw doubt on the description 
of almost every genus that is not recorded as pentamerous in 
the Genera Insectorum. In this stage of the investigation, there- 
fore, two important questions arise, which require much more 
development than I am able to give them in the present crude 
sketch. "These are, first, What coleopterous genera possess only 
four joints to each of their tarsi? and, secondly, Considering such 
tetramerous tarsi as typically pentamerous, what articulation is it 
that is evanescent in these genera? Such are questions intimately 
connected with the doctrine of natural affinities, as it relates to 
Coleoptera; and I therefore beg leave to conclude this paper 
with a few remarks, which may be interesting to those who may 
be inclined to take up the subject. 
Heteromerous insects are, as before said, so called by MM. Du- 
meril and Latreille because they have five articulations to each of 
the four first tarsi, and only four to each of the two last. This, as 
* In his first letter to the editors of the Philosophical Magazine, Mr. Kirby states, 
on the authority of Mr. Spence, that Müller had discovered the third joint in the tarsus 
of Coccinella; but as Mr. Kirby has not been able to refer me to the work in which 
Müller published this discovery respecting the Trimera of the French system, I can 
only mention the fact, contenting myself, in consequence, with having been the first to 
make known to the public the true construction of the tarsus in the insects called 
Tetramera by the French entomologists.— May 1825. , 
ar 
