614 Mr. D. Sharp and Mr. F. Muir on the Comparative 
We have omitted from our tentative tables certain 
families that we have examined, e. g. Trichopterygidae and 
Discolomidae, but we have been somewhat inconsistent, 
inasmuch as we have inserted others that are perhaps 
quite as doubtful. Any one who will examine such forms 
as Cerylon will appreciate the difficulty as to making a 
correct conclusion as to the morphology of the aedeagus 
in these exceptional cases; the examination of a series of 
allied forms is often imperative before coming to a positive 
conclusion. 
We must also reiterate here what we have said else- 
where as to the “Spicule.” This is scarcely touched on 
by us, because it would have involved us in the considera- 
tion of the number of abdominal segments; but we 
recognise the importance of the subject. A comparative 
study of this sclerite, together with the terminal body 
segments, is necessary before a final decision can be 
reached for taxonomical purposes. 
At present we are disposed to adopt eight series. We 
have considered the possible relations of these series in 
the section on phylogeny. 
(1) BYRRHOIDEA. 
Under this name we include twenty or thirty families. 
The complex is of considerable importance, as it is possible 
to consider that we are here in the presence of the more 
primitive of the conditions of the Coleopterous genital 
tube, so far as existing forms are concerned. We use this 
qualification because the structures are very far from 
being truly primitive. The peculiarities of this complex 
may be thus summarised, viz.: A median lobe, bearing 
(as in other cases) the orifice of the duct, and on each side 
of it a lateral lobe, the sclerites being intimately connected 
with a basal-piece. The tegmen is thus very complete, 
and the relation between it and the median lobe is one 
that allows of very little movement backwards and for- 
wards of the median lobe independent of the tegmen. 
This distinguishes the families from the Cucujoidea. 
Moreover, the sac is never highly specialised, in many 
cases is scarcely differentiated from the duct. 
The Buprestidae are peculiar, possessing a remarkable 
coadaptation between the inner aspects of the lateral lobes 
and the median lobe, which permits the median lobe to 
glide backwards and forwards in the slots of the lateral 
