20 
THE ANATOMY OF ARGAS PERSICUS 
(OKEN 1818). 
PART I. 
By L. E. ROBINSON, A.R.C.Sc. Bond., 
AND J. DAVIDSON, M.Sc. Liverpool. 
{From the Cooper Laboratory for Economic Research, Watford.) 
(With Plates I to VI and 2 Text-figures.) 
Introduction. 
The importance of the Argasidae, in relation to the transmission of 
disease, has suggested the need of a moderately detailed description of 
the anatomy of an example of the family. With the object of supplying 
this want, the authors have made a study of a widely distributed species 
—Argas persicus —and they venture to hope that the work embodied 
in the following pages will furnish something towards the much-needed 
information, the present lack of which adds to the many difficulties 
which are encountered in investigations concerning the life-stages of 
pathogenic Haematozoa. 
That Argas g)ersiciis plays a role in the transmission of Spiro- 
chaetosis of domesticated birds is now common knowdedge. Apart 
from this association, however, this tick is one of the most troublesome 
pests which affect poultry, killing enormous numbers of birds from the 
loss of blood and the “ tick-worry ” consequent upon its bites. 
The species has a remarkably wide range of distribution. From the 
map (Text-fig. 1) it is seen that in practically all the countries lying 
between the fortieth parallels of north and south latitude Argas 
persicus is known to exist, and there is little doubt that, as time goes 
on, new records of its occurrence will fill many of the emptj" spaces 
