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Figures 8 and 9, Q, slightly engorged, dorsal and ventral views KEY MORPHOLOGICAL CHARACTERS, FAMILY ARGASIDAE Ornithodoros savignyi (Egyptian specimen)
Figure 10, d, genital area
Six Argas species occur in the Sudan. Four or possibly five other rare kinds have been recorded elsewhere in Africa. All the Sudan species may bite man, and, except possibly for the bat parasites, all may cause more or less painful sequelae. Insofar as our present knowledge goes, Argas ticks are rarely known to transmit human disease. Birds and #. are the chief hosts of most Argas species. The more widely spread species that parasitize domestic fowls are often serious pests and important vectors of avian diseases. The bat-infesting species also range rather widely and may possibly disseminate pathogenic organisms among their hosts.
Larval Argas ticks, in contrast to the two well-known African argasids, Ornithodoros moubata and 0. #: are all active, suck blood, and often may be observed feeding on their hosts. Argas nymphs and adults, like those of Ornithodoros, are usually found only by careful searching in niches and concealed resting places in the immediate habitat of their favorite host.
Ticks of the genus Argas, unless recently engorged, are usually flatter in profile than Ornithodoros, and can in most instances be easily distinguished from them by the presence of some morphological differentiation of the peripheral integument of the body.
Argas ticks are still surprisingly poorly known in most parts of the World and considerably larger collections, more data on their life history, and more exact collecting data are necessary before the biology and systematics of this genus can be finally settled.
The other species of # known to occur in Africa, some of which undoubtedly will be fo in the Sudan, are the following:
A. aequalis (Neumann, 1901) from Tanganyika. The host is unknown # apparently only the original collection is known. Originally described in the genus Ornithodoros but subsequently referred to Argas (Neumann 1908B).
A. hermanni (Audouin, 1827) from Egypt. Neumann (1896) noted material
" " from Ethiopia and Hoogstraal (1952A) from bird nests in Egypt. We are still studying material referable to this species in view of its possibly unsatisfactory taxonomic criteria and species Status.
A. striatus Bedford (1932A,1934) from weaver bird nests, Cape Prov
*- ince, South Africa. This species is said to be closely related to A. aequalis, but both are in need of comparative biological and morphological studies.
A. transgariepinus (White, 1846) from South Africa. A. kochi (Neumann, # from Basutoland possibly is a synonym. Berlese (1913) reported specimens biting a child and walking on the wall of a bank in Italy. Hoogstraal (1952A) described biology in Egyptian bat caves. Hoogstraal (1954C) noted presence in Spain. A report on a study of the life cycle, biology, and morphology of each stage will be presented in a forthcoming paper.
Subgeneric classifications are not included for other groups in this work because their status is still moot. The issue has been forced in the genus Argas by the necessity for deciding whether to refer to some species generically as Carios, Ogadenus, or Argas. Studies on this subject are presently under way and will be reported more fully elsewhere.