District, this tampan appears to be more uniformly distributed than elsewhere. These details, however, await confirmation.

Outward from the Somali District the eyeless tampan normally inhabits dry structures in savannah areas, especially those with sandy or sandy clay soils with light woods. Riparian forests through grasslands, dense forests, and areas of heavy rainfall are usually free of the tick, although exceptional human culture patterns sometimes allow important foci to develop in dry habitats in these situations. Such details have been described most vividly by workers in the Belgian Congo (Bequaert 1919,1930A; Rodhain 1919A,B,1922A,C; Ghesquiere 1922; Schwetz 1932,1933A,1942, 1943; and others).

0. moubata appears to have spread gradually outward from somewhat dry areas of East Africa along main paths of human trav_ el. Old Arabic slave routes are considered to have been largely responsible for its initial distribution by man (Dutton and Todd 1905A; Bequaert 1919,1930A). Although especially common along important old and new travel arteries, the tampan is often mark edly absent a few miles distant. Exceptions do occur. For instance, Koch (1905) reported 0. moubata from the Rubafu Moun tains and elsewhere in villages away from trade routes in Tanganyika. More and more exceptions should occur as travel becomes easier and quicker, tribal customs disintegrate, and labor demands call numerous individuals, with possibly tick-infested personal effects, far from their usual range of activities.

0. moubata is said to be frequently concealed in sleeping mats, spare clothing, or baskets and thus may be transferred easily from one area to another. South African authorities blame the tampan's increasing spread in the Union on migratory laborers from Nyasaland and Portugese territories. In the Belgian Congo it has been found in potato baskets sent to distant markets (Ghesquiere 1922) and is frequently introduced in goods sent from the lowlands to villages at high elevations (Schouteden 1928). This tampan is common in fish baskets of vendors bicycling from Lake Nyasa and Lake Shirwa to villages in other parts of Nyasa land (Hardman 1951). Christy (1903A,B) collected specimens in salt bags being transported between Lake Albert and Tete.

Where soil consistency permits, the eyeless tampan usually burrows to a depth of approximately an inch; but in soil cracks it burrows deeper. On the ground surface it may rest under any object that offers shelter. If soil is too wet or too hard for burrowing the tick is induced to crawl up walls and seek con cealment behind hanging objects, in cracks or in ceilings. The tampan's presence is often indicated by spots or streaks from its excretory products left on walls.

In Kenya, O. moubata ranges from sea level to an elevation of 8000 feet (Lewis 1939A) or of 9000 (Heisch 1950A). In Ethiopia, Manson Bahr (1941) stated it is absent above 6000 feet elevation and Scaffidi (1937) reported that it is not present above 7150 feet.

This tampan survives in the Transvaal Highveld in spite of 'bitterly cold winters" there (De Meillon 1940, Ordman 1941). Theiler reports (correspondence) that winter day-temperatures in the Transvaal highlands are "high enough" and that residents bring fires into their huts at night.

In certain Congo areas, Flamand (1928) found 0. moubata thriving at about 10,000 feet elevation. Schouteden (1928) replied that these populations are the result of repeated introductions in goods from the lowlands. While tampans survive at these altitudes, they do not reproduce there.

Incidental to a disease transmission study, Van Oye (1943) reported that 0. moubata dies in less than 24 hours at tempera tures of 0°C. to 5oC. (41°F.). 41°F.). However, Burgdorfer reports (con versation) that he has maintained tampans at 3°C. for at least ten days without death of the specimens. Feng and Chung (1938) maintained these ticks alive for months at 5°C. to 8°C. It is obvious that the critical temperature range for the survival of 0. moubata requires further study.

The absence of 0. moubata from certain volcanic areas in the Congo was thought by Van Saceghem (1923) to be owing to an un favorable chemical action produced by contact of lava with oxygen of the air. Dr. J. Bequaert reports (conversation) that these areas are all at high elevation and that he believes altitude to be the important limiting factor in these volcanic areas.

Wallace (1913) noted that in Northern Rhodesia 0. moubata abounded in hilly country and on the Mpika plateau, but was ab sent in the hot Luangwa Valley. The combinations of temperature and relative humidity factors that restrict 0. moubata in nature are still poorly known.

Dutton and Todd (1905A,B) and Bequaert (1919) mentioned an exception to the general rule that 0. moubata does not occur in deeply forested, humid areas. The explanation was that infestations in the Upper Ituri Forest are in wooded areas where arab isized Negro inhabitants have cut over extensive forests and constructed villages of dry, permanent buildings. In these, ticks brought along the Arab trade route have been able to survive in spite of inclement conditions outside.

Another notable exception to the usual finding that 0. moubata is absent from high rainfall areas is cited by Walton (1950A). In Meru District, Kenya, even under unfavorable high rainfall and humidity conditions, large populations of this tick survive in some huts. The predisposing factor is that the local tribes sleep on dry, raised mud beds. Hosts are readily accessible to ticks and fires near beds keep an area of ground dry enough to meet the tampan's requirements. Agricultural implements in these huts provide additional shelters behind and under which the ticks also hide. Contrary to usual advice to remove domestic animals from human habitations, Walton believes that under Meru District conditions animals provide enough extra humidity and pound floors hard enough to reduce tick populations. Under more usual conditions, however, this suggestion would probably not be an effective one. In some Meru District huts, where sticky soil has a humidity of about 90%, it is difficult for ticks to burrow and few specimens are found. Whether this investigator searched for ticks climbing walls or pillars in these huts is not stated.

At Kisumu, Heisch (1950) found that the size of tampan popu lations in huts is uninfluenced by seasonal variation in rainfall.

Knowles and Terry (1950) collected hundreds of nymphal tampans on fowls kept in human habitations in Tanganyika, but Phipps (1950) asserted that chickens are seldom infested there. Careful research into the highly practical problem of relationship of chickens to

tampan infestation is indicated. Rodhain (1919A) reported finding avian blood in specimens taken from an empty outhouse inhabited by chickens. It has been suggested that periodic forays by chickens into infested huts may partially reduce the tick population in these places.

Aside from usual indigenous dwellings, the eyeless tampan is frequently encountered where people congregate. In Uganda, rest camps often have been burned because of heavy infestation (Bruce et al 1911); jails and semi permanent buildings used by itinerant Africans are frequently infested (Hopkins and Chorley 1940). In Kenya, 0. moubata is "alarmingly abundant" in labor camps (Jepson 1947) and military barracks are specially constructed to resist infestation (Hynd 1945). The tampan is a coffeehouse inhabitant in British Somaliland (Anderson 1947). In a Somaliland focus of relapsing fever, all patients were found to be members of a polit ical party the headquarters building of which was infested with 0. moubata and had escaped insecticiding when other structures were Justed (Lipparoni 1951). In South Africa, it is an important pest in lesser mine" labor camps but in larger mines, such as those at Johannesburg where sanitary measures are practiced, the tick is absent (Ordman 1941,1943).

In contrast, the closely-related eyed tampan, O. savignyi, usually lives away from habitations, under trees, in village squares, near wells, in stockades, or in shaded spots along trails where men and animals rest.

There are but few reported observations of 0. moubata living under outdoor conditions approaching those favored by 0. savignyi. In 1916, Belgian colonial troops operating in Urundi, while tent ing under a row of mango trees that had bordered buildings destroyed some six years earlier, recovered several specimens from the soil around the roots of these trees. The assumption was that these ticks had survived since the destruction of the nearby buildings some years earlier (Rodhain 1919B).

Ordman (1941) listed two cases of the eyeless tampan in South Africa living "in and under trees", but further conclusive evidence is not presented.

In various editions of Brumpt's "Precis," 0. moubata is con sidered as an outdoor as well as an indoor species. There is, however, no published evidence to support the supposition that this species normally lives away from human structures, except in large animal burrows and in pigsties. Rare exceptions, such as ticks remaining in the area after a building is destroyed, or dropping from a bedding roll during transit, must be expected. Further search may, of course, show that the tampan has a broader range of habitats than present evidence indicates.

Wild Habitats

A gradually increasing body of information indicates the not uncommon occurrence of 0. moubata in large animal burrows through out tropical and southern Africa (see HOSTS above). The relation ship of these populations to those of human habitations awaits determination. The environment of infested burrows has been only briefly described and it is not known whether wild populations have the same temperature and humidity requirements as domestic populations.

In Tanganyika burrows, Walton (1953) observed tampans clinging to the roof close to the entrance as though waiting for some animal to squeeze past. Ticks were found among the hair of the back of warthogs shot in the early morning. In the burrows, temperature was 75°F. and relative humidity of the soil 77%. Other infested Tanga nyika burrows examined by Geigy and Mooser (1955) with thermohygro meters showed that the microclimate of these holes corresponded closely to that observed by them in infested native huts (details not stated).

Discovery of numerous specimens in large burrows in several widely scattered parts of Kenya has led Heisch and Grainger (1950) to speculate on the relationships between wild and domestic popu lations of eyeless tampans. The ticks were obviously breeding in these burrows that originally had been dug by antbears and later were inhabited by porcupines or warthogs. Other specimens were found in large burrows on a long-isolated Lake Naivasha island seldom visited by man. Heisch and Grainger conjecture that large burrows were the original or primitive home of the eyeless tampan and that it later became adapted to human habitations. The several reports of 0. moubata from burrow-inhabiting warthogs, porcupines.