588 APPENDIX. 
refer to the bone of the hip. Secondly, from a careful examination of some 
species of every order of insects, I am now persuaded that both Illiger and 
we are wrong, also, in considering the Cora as formed of two parts, and the 
Ischium as forming one of them, On the contrary, it is clearly a part of 
the thigh, to which it is generally closely attached by a membrane admitting 
only a very slight degree of motion, but perhaps never by a distinct joint. 
The joint is always between the Ilium and the Ischium, the latter serving 
as a sort of fulcrum to the base of the thigh, often with a hole between them 
for the reception of the pivot of the Ilium. If you will dissect and examine 
a large foreign Geotrupes, you will sce all this very clearly. You will find 
that even when the insect has had its joints made pliant by being immersed 
in hot water, there is little or no motion can be produced between the Ischium 
and the thigh, which are attached to each other by that articulation called 
by anatomists amphiarthrosis; whereas there is a distinct ginglymus joint be- 
tween the Ilium and the Ischium. It is true that in Hymenoptera, Diptera, 
and some Coleoptera, where the Ischia are not fixed obliquely to the base 
of the thigh, but ¢ransversely, the Ilium and Ischium do seem at first view 
like the two. parts of one joint; but even then, as I have ascertained by 
examining living insects, the Ischium is still fixed to the thigh by # mem- 
brane and no joint, and the joint is still between the Ischium and Ilium, 
Now, such being the facts, there cannot, I think, be a moment’s hesitation 
in deciding that it can never be proper to consider a part as forming a portion 
of a limb with which it is connected by a true ginglymus joint; or not to 
consider it as portion of a limb with which in many cases it seems truly 
connate, and in all others closely connected by 2 membrane admitting of little 
or no motion. It appears to me, therefore, that our Ilium should be regarded 
as a peculiar and distinct joint, namely, the true hip-joint; and we cannot 
haye a better name for it than Cora, which Latreille also gives to it. Our 
Ischium must be considered part of the thigh, and cannot, I think, have a 
better name than Trochanter, which has the right of priority, and, though not 
strictly anatomically correct, is as near as in such cases we can expect to 
come: both are processes of the base of the thigh; only in man the trochanter 
is a mere projection of the base of the thigh; in insects a distinct part 
joined by a suture and membrane. Observe, some Ichneumons have a double 
trochanter. 
“TJ particularly wish you would examine the claw-joint of the tarsi of a 
large Cerambyx, Leptura, or Chrysomela, and I think you will agree with me 
that the small part of the base, though separated by a suture, is no distinct 
joint, but in fact a trochanter affixed to the claw-joint by the anarthrosis articu- 
lation, and very closely analogous to the trochanters of the thighs. ‘To me it 
seems that it would be quite as proper to consider this minute basal part a por- 
tion of the third joint (not of the claw-joint) of the tarsi as to call the trochan- 
ters parts of the Cox. Attention to the mode of articulation (evidently a 
material point) will lead to another good consequence— we can thus avoid 
regarding this supplementary part in the tarsi of Zeptura, &c. as a true joint, 
the reverse of which would sadly curtail our grand divisions founded on the 
tarsi; and, by calling it a trochanter, we may possibly gain some good generic 
as if, as I suspect, the same circumstance holds good in some other 
tribes. 
“TI have been puzzling myself a good deal to discover what parts in the 
postpectus of Hymenoptera and Coleoptera are analogous to each other. I have 
not yet by any means satisfied myself on every point, but two or three fixed 
landmarks I think I haye ascertained. One is, that your Collare (‘ Monograph. 
Apum Ang.’) is not, as we have supposed, analogous to the upper part of the 
thorax in Coleoptera. Iwas made pretty sure of this in the course of dissect- 
