Volume V 
FEBRUARY, 1912 
No. 1 
NOTES ON THE GENUS RHIPICEPHALUS, WITH 
THE DESCRIPTION OF NEW SPECIES, AND THE 
CONSIDERATION OF SOME SPECIES HITHERTO 
DESCRIBED. 
By CECIL WARBURTON, M.A., F.Z.S. 
Zoologist to the Royal Agricultural Society of England, and Demonstrator 
hi Medical Entomology to the Quick Professor at Cambridge. 
{From the Quick Lahoi'atory, University of Cambridge.) 
(With 12 Text-figures.) 
The identification of species of Rhipicephalus is likely to give more 
trouble than is the case with' any other genus of Txodidae, for while, on 
the one hand, there are few species which depart greatly from the 
general type, on the other hand the range of variation within the 
species is extremely great. In no genus is it so dangerous to describe 
a new species from a single individual, especially if the specimen be a 
female. 
The structural features which are fairly constant in a species are 
few, and not very easy of determination ; for example, the exact shape of 
the basis capituli in the male is of the first importance, but a slight 
error of orientation under the microscope will considerably alter its 
apparent outline. There are two reasons for this: first, the dorsal 
surface of the body and that of the capitulum are usually in slightly 
different planes, so that when the body is horizontal the capitulum 
is depressed and fore-shortened; in the second place, as Dbnitz (1910, 
p. 465) has already pointed out, the antero-lateral border of the basis 
capituli is not, like the postero-lateral border, a definite edge, but is a 
rounded surface, and a faulty impression of the degree of salience and 
Parasitology v • 1 
