9

seminal fluid reached the palps which, judging from their analogy with those
of spiders, should be accessory organs of copulation. From anatomical
considerations which are discussed later, there can be no doubt that the male
passes into the vulva of the female one or more spermatophores, or sacs
containing a large number of spermatozoa (see Sect. V, p. 24).

        The female, after finally attaching herself, steadily distends with blood.
The time during which she remains on the host varies with the species. In the
case of some species it may be as short as twenty-four hours. During this time
the tick increases enormously in size, the body becoming enlarged out of all
proportion to the rostrum and legs. If an attempt be made to remove a tick at this
time, considerable force is necessary and the mouth parts are practically torn
from their situation in the tissues. When fully gorged the female tick drops to
the ground and shortly deposits her ova. After or during this act the female
dies. The males do not become gorged in the same manner as the female and
are therefore less conspicuous.

        The Argasidæ.—The habits of the family have been described in the case
of A. miniatus, the American fowl tick, A. reflexus, the pigeon tick, O. savignyi
(Audouin), O. moubata and a few others. The different species show in the
main the same characteristics. My own observations have been made upon
O. savignyi (Audouin).

        The general behaviour of these ticks is quite unlike that of the cattle ticks.
As would be gathered from the accounts of travellers, ticks of the genus are
mainly nocturnal in their habits, and conceal themselves by day. The specimens
from Tiripati buried themselves partly or wholly in the gravel during the day, but
issued forth at evening-time, and ran quickly about. At times, especially if one
breathes upon or gently disturbs the gravel, the ticks display considerable
excitement. If handled they at once sham death. In this condition the legs are
closely applied to the body and the tick is readily overlooked among fragments
of stick and stone. When running about, the ticks often exhibit a curious habit
of raising the first pair of legs, as though receiving in this way information as
regards their surroundings. When ticks were placed in glass or porcelain
vessels, a rapid tapping sound was sometimes heard. This appeared to be
due to a vibration of the hinder portion of the body, which was seen to occur
from time to time.

        Ornithodorus savignyi is exceptionally hardy and can live many months
without food or moisture. Specimens are sent to me in perforated tin cannisters,
together with a quantity of the gravel in which they are found. Although the
journey by post takes forty-eight hours, the ticks invariably arrive in a living
condition. Placed in a dish with a little gravel, many of the ticks have lived
without food for over four months.

C