E.
ANEURIN
LEWIS
385
The Amblyomma species seem, on the whole, to be less selective than other
ticks, or they can tolerate better conditions of relatively wide differences.
They are not often found in forests. A. variegatum thrives all over the ranching
country of the Masai Reserve, throughout the cultivated areas of Kavirondo,
Kikuyu, and Ukamba ; and in the semi-desert areas in the north and east of
Kenya Colony. It is widely distributed over the European farms (where
dipping has not eliminated the species), whether these are of the purely stock
class or mainly concerned with crop-production. A. variegatum exists at
8,200 ft. at Timboroa, at 3,800 ft. around the shores of Lake Victoria, and at
sea-level. A. gemma evidently prefers a warmer and drier climate than A.
variegatum and is not so extensively distributed. A. lepidum prevails in typical
desert country and is mostly found in the north-west of Kenya, in parts of
Uganda, and farther south in Tanganyika.
I. pilosus is a species of the hills and mountain or forest areas rather than
of the lowlands. It infests cattle, sheep, and goats on the slopes of the es-
carpments of the Great Rift, in the forested areas of the Aberdares, on the
Mau hills, in the Thompson's Falls and Limuru districts. Wild animals are
often infested with this ' paralysis ' tick. Other species are more frequently
found on game and wild birds, I. rasus, in its larval phase, being common
tick of small and large birds.
R. appendiculatus is the most important tick as far as stock-farming in
Kenya is concerned. Its distribution is better known than that of other
species. Yet much remains to be done even with regard to this tick. Its
normal distribution in most of the advanced European areas has been distur-
bed by dipping and other methods of control that have been employed for
many years. It persists in relatively small numbers where control has not
been consistently maintained. The tick known as the common brown tick
is usually found in greatest abundance at elevations between 4,800 ft. and
7,000 ft. ; but it extends into higher country where the vegetational cover
reduces the more severe conditions of exposed pastures. It penetrates into
lower country also, where the general environment is modified by the vegeta-
tion and local climate. The most heavily infested, or enzootic, areas appear to
be those where cultivation predominates and where the infestation of stock
is not attended to, as on the majority of stock farms. The plains are usually
free of this tick and it is not often found on the high plateaux or in desert
areas.
O. moubata and savignyi are generally looked upon as ticks of the dry, hot
and sandy deserts. Their presence in Kenya seemed to be confined to the
Northern Frontier Province (3,300 ft.) the eastern areas down the Tana river,
and the coastal belt. At one time the former species was a common pest in
the Kavirondo Reserves and on the lake shores (3,800 ft.). More recently,
however, the writer has obtained large numbers of O. moubata from huts on
the site of goat enclosures, 8,000 ft. above sea-level.
Arges persicus occurs in isolated localities in Kenya. It is believed not to
be indigenous, as the records indicate that it exists only in European areas.
The true distribution of this tick may come to light with a growing interest in
poultry and their parasites.