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It should be noted that argasid ticks in general are xerophilic animals. Many students of their life cycle have failed to recognize this important fact. Although in localities of extremely low relative humidity argasids may seek a somewhat more humid microhabitat, these niches are seldom those with a significantly high relative humidity. The few species extending into the humid tropics choose dry niches in dry habitats and do not thrive away from these re. treats. Within this range, individual species have varying degrees of tolerance.
Examination of bird nests, caves, bat roosts, animal lairs, burrows, rodent nests, hyrax dens, a.nd big game resting and rolling areas in the Sudan will undoubtedly reveal unrecorded or possibly even undescribed argasid species. Although of considerable medical importance a.nd zoological interest, these ticks are not frequently collected because specialized efforts a.nd techniques are necessary to obtain them. Sifting of soil or sand in animal burrows, caves, or dens is often most fruitful. Examination of rock interstices and searching under stones is also important in some situations. In. vestigation of bird nests, especially those of larger birds, should yield much interesting data. There is little doubt that at least one Ar as parasite of birds, and Ornithodoros erraticus remain to be fo in the Sudan, in addition to _5. deIano'§I E some member of the Q. tholozani group.
Figures 8 and 9, Q, slightly engorged, dorsal and ventral views KEY MCRPHOIDGICAL CHARACTERS, FAMILY ARGASIDAE
EV“ \ Spurocle T'°°"°"'e' '*‘ ' Suorocoxcl fold Fwy ‘ |bIO \ ' Mefotorsus /
Dorsal humps ~
Subopicoi dorsd — 0notuOerOr\_ce
Figure 10, d‘, genital area
Six Ar as species occur in the Sudan. Four or possibly five other rare nds have been recorded elsewhere in Africa. All the Sudan species may bite man, and, except possibly for the bat para. sites, all may cause more or less painful sequelae. Insofar as our present knowledge goes, Ar as ticks are rarely known to trans. mit human disease. Birds and Eats are the chief hsts of most Ar as species. The nore widely spread species that perasitize 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.
Ierval Ar as ticks, in contrast to the two well.known African argasids, Orn t oros moubata and Q. sawi , are all active, suck blood, and often may Be o5§erved feeding on ir hosts. Ar as nymphs and adults, like those of Ornithodoros, are usually ound only by careful searching in niches Z53 concealed resting places in the immediate habitat of their favorite host.
Ticks of the genus Argas, unless recently engorged, are usual. ly flatter in profile than Ornithodoros, and can in most instances
be easily distinguished from them 5; the presence of some morpholog. ical differentiation of the peripheral integument of te 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 Ar as known to occur in Africa, some of which undoubtedly will be fofind in the Sudan, are the following:
‘Q. a ualis (Neumann, 1901) from Tanganyika. The host is unknown
ly 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 (19525) from bird nests in Egypt. We are still studying mterial referable to this species in view of its possibly unsatisfactory taxonomic criteria and species
5. striatus Bedford (l932A,l934) from weaver bird nests, Cape Prov. Ece, South Africa. This species is said to be closely related to A. ae ualis, but both are in need of comparative biological
and_morp gical studies.
5. trans arie inus (White, 1846) from South Africa. 5. kochi (Neu. nnnn, Ifi’ from Basutoland possibly is a synonym. Berlese
(1913) reported specimens biting a child and walking on the wall of a bank in Italy. Hoogstraal (195211) described biology in Egptian bat caves. Hoogstraal (19540) 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
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, 0 adenus, or Argas. Stmiies on this subject are presently er way will be reported nnre fully elsewhere.