(3 
Rhiiricephcdm 
are not a few forms which have been described either from very scanty 
material, or from a considerable number of examples taken on a single 
occasion, and presenting no very salient characteristics. Our experience 
in the case of the better known “ species ” makes it probable that, if 
a large number of examples were available for study, even those charac¬ 
teristics which appear to distinguish them would fail in the all-important 
quality of constancy. It is clear, then, that the taxonomy of Rhipi- 
cephalus is bound to be unsatisfactory, and the question to be solved 
is what way of tackling it is likely to be of most use to those who have 
to deal with the group. Forms merging into one another by imper¬ 
ceptible gradations are not, scientifically, distinct species—nor even 
distinct varieties ; yet to insist on this, and to fuse together such 
obviously different forms as, for example, R. simus and R. falcatus, 
would lead to inextricable confusion, and it seems better to assign the 
term species, under protest, so to speak, to forms sufficiently distinct 
where characteristic individuals are considered, though cases are sure 
to arise in which an example can be attributed with equal justice to 
either of two such “ species,” and it may be even necessary to describe 
it by connecting with a hyphen two “ specific ” names—as R. simus- 
falcatus. The systematist has no need to apologise for a want of 
definiteness the responsibility for which lies with Nature herself. 
It is from this point of view that the subjoined new “species” of 
Rhipicephalus are described, and the case of the first— R. neavei 
(see p. 7)—may be dealt with a little more fully. 
Among a large number of tubes of ticks received from Nyasaland, 
N. Rhodesia and British E. Africa the constant recurrence of a certain 
form—very characteristic in well-marked examples—was noted. It 
seemed incredible that a tick evidently so common in those regions had 
remained undescribed, and yet it seemed impossible to recognise it as 
at all a normal form of any of the species whose establishment has been 
based on a considerable number of specimens. It bears a superficial 
resemblance to R. appendicidatus, but differs from it in what must be 
regarded as among the most constant characteristics of the male—the 
shape of the basis capituli, and the anal plates. Of the species based 
upon few examples and possessing no very salient characteristics it 
seemed, from descriptions, to have affinities with one or two—notably 
R. kochi, but the types of this species have been examined with a 
negative result. We have here, then, a form of Rhipicephalus which 
has at least as good a title to rank as a distinct species as the majority 
of those already recognised, though if only two or three examples had 
