534. Dr. H. Eltringham on the 
differences are of the slightest and by no means so great as 
the outward variations of undoubted forms of the same 
species, only to find that the respective armatures are so 
completely distinct that specific identity is out of the 
question. 
Furthermore, there are forms, the external facies of 
which are so utterly different that we are bound to regard 
them as well-separated species, but the male armatures 
are not merely doubtfully distinguishable but of a highly 
complex form. 
The form of the male armature also raises another 
question. Given several distinct types of structure in 
these organs, each type being broadly distinguishable from 
the others, how far are we Justified in assuming that the 
members of the genus referable to one particular type of 
armature are necessarily more nearly related to each other 
_than to species whose armatures fall under another type— 
that, in fact, they form an intra-generic group? If we do 
this with Neptis it is true that the majority of forms in 
groups so constituted seem fairly naturally associated, but 
at the same time there are instances in which two or more 
forms of totally different outward facies have armatures 
which are not constantly distinguishable. Thus trigono- 
phora and kikideli are apparently widely separated, and yet 
it would be impossible to decide from a number of prepara- 
tions which belonged to the former and which to the 
latter. This is not a question of a very simple structure of 
the armatures, since the claspers of these two species are of 
a curious form considerably elaborated and totally unlike 
those of any other African species. 
A far more complicated case is that of the forms which 
include ochracea, exaleuca, woodwardi, swynnerton, incon- 
grua, and other species. At first sight the only difference 
between exaleuca and ochracea is that of colour. Griinberg 
on one occasion referred to an example of ochracea as 
exaleuca var. ochracea, a terminology I should have been 
inclined to support in the absence of anatomical prepara- 
tions. Nevertheless, we find that whilst the claspers in 
ochracea are of fairly constant form, and that a peculiarly 
specialised one, those of ewaleuca are extremely variable, 
though none of the variations resembles the clasper of 
ochracea. Close as is the resemblance between these two 
species in everything except colour, the clasper of ochracea, 
whilst apparently constantly distinguishable from that of 
