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host into the southern periphery of the host's range should be considered in view of its apparent total absence on elephants in Bahr El Ghazal Province of the Sudan.7

HOSTS

All authors list the African elephant, Loxodonta africana subspp., as chief host. Uncommon hosts that have been reported for a few specimens are: gazelle (Neumann 1901,1907,1910B), antelope and domestic horse (Neumann 1911), rhinoceros (Neumann 1922), leopard (Robinson 1926), bushpig and large lizard (Schwetz 1927B), domestic dog (Santos Dias 1953B) and buffalo (Hoogstraal 1954C). Dr. Theiler has larvae, nymphs, and a male specimen from a bird, Pitta reichenowi, another indication of ground birds as hosts of immature Amblyomma species. In our collection are several nymphs and a male with massive legs taken from a hippopo tamus in Kazinga Channel of Lake Edward by Lt. Colonel Don Davis, U.S. Army. Miss J. B. Walker has a collection consisting of seven males and four females from a Tanganyika black rhinoceros; also others from an elephant there.

The small nymph collected at Lokila, Equatoria, from a chameleon by E. T. M. Reid is an unusual record. Santos Dias (19480) states that larvae and nymphs are rarely found on elephants. The only other records for nymphal hosts in nature are those of the bird and hippopotamus listed above, and one nymph in the Onderstepoort collection (Theiler, unpublished) with adults, from an elephant at Toro, Uganda.

BIOLOGY

Adult specimens of the elephant amblyomma may be found on any part of the host's body, Immature stages previously have been reported only by Santos Dias (19420), who states that larvae and nymphs are rarely taken on elephants. Santos Dias experiment ally reared larvae and nymphs on guinea pigs and reported that six months were required to complete the three host life cycle. He observed a chalcid wasp parasite, Hunterellus hookeri, infesting nymphs. Fiasson (1943B) reported 3000 egcs from an engorged female.

No spec

Mr. J. Owen, who furnished the 197 specimens from a single elephant in a plains herd passing through Lotti Forest, reported that his "boys" could have collected at least twice as many from this elephant if they had had more containers for them. imens other than the few listed could be found on the three other Equatoria Province elephants noted above. Numerous other newly killed elephants in this Province have been examined with out finding ticks of any sort.

DISEASE RELATIONS

A. tholloni is possibly a vector of Nuttallia loxodontis of elephants.

REMARKS

The stage to stage growth of A. tholloni has been charted by Campana Rouget (1954). Misshapen specimens have been described and illustrated by Santos Dias (1947B, 1949,1955A).

Larval and nymphal stages of A. tholloni were described and illustrated by Santos Dias (1949D).

Variations in male scut al patterns from Mozambique were il lustrated by Santos Dias (1947A). Within the geographical range of the elephant amblyomma there are two scutal color patterns, one drab and lightly pigmented with small areas of color, the other brightly marked, usually with more extensive pigmented areas. The bright form is particularly common among numerous specimens seen from West Africa and rare among those from East Africa; the drab form is common in East African specimen and rare in West African material. After having examined all of the numerous A. tholloni specimens in British Museum (fatural History) collections, which represent almost all areas of the geographic range of this species, one may only conclude that these two color patterns do not appear to be genetic variants and are probably not associated with temperature or rainfall factors or with methods of preservation. They may possibly derive from nutritional factors. A biological study of living specimens is the

only means of determining the reason for these two color patterns.

Since the above was written, Raceau (1953B) has reported that Cameroons specimens and others that he has seen from French Equatorial Africa all show the reduction in ornamentation that has appeared to me to be more common in East than in West African specimens.7

Robinson (1926) stated that a large pale spot in each lateral field of the scutum and a stout spur on coxa IV are female diagnostic characters. I have examined Nuttall's lot 3381 in British Museum (Natural History), on which Robinson's species definition and illustrations were based, and find it to be the most heavily and liberally ornamented material, along with a few others from Sierra Leone, of any representatives of this species in the col lection. Actually, lateral field pale spots are absent in most of these specimens. The stoutness of the spur on coxa I is also a variable character and the specimen selected by Robinson is an extreme example. In most specimens, this spur is merely a small pointed projection from or near the posterior coxal margin.

Ali. Sudan specimens at hand are drably colored and their pigmented areas are no more extensive than those illustrated (Figure 90). On some, ornamentation is almost obsolete.

IDENTIFICATION

Males. No other African amblyomma can be confused with this species because of the smallness of its pigmented areas, flat eyes, and absence of both lateral grooves and of large scutal punctations. Males measure about 5.0 mm. long and 4.0 mm. wide.

Females are equally easily distinguished from all others in Africa by the absence of large scut al punctations, triangular scutal shape with narrow posterior margin, and distribution of color pattern that is usually only an irregular spot in the posterior point but sometimes also has small lateral spots.

The cervical grooves are short and eyes are large, flat, and pale, Females, unengorged, are usually about 6.0 mn. long and 4.7 mm. wide.

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[graphic][subsumed][subsumed][subsumed][subsumed]

Figures 92 and 93, o, dorsal and ventral views Figures 94 and 95, , dorsal and ventral views

AT BLYOMMA VARIEGATUM

Sudan Specimens

PLATE XXXI

- 259

AMBLYOMMA VARIEGATUM (Fabricius, 1794).

(Figures 92 to 95)

THE TROPICAL BONT TICK

L NO

EQUATORIA PROVINCE RECORDS

3

1
Ikoto
MAN (feeding on)

Feb
1
Torit
Atelerix pruneri oweni

Nov
6
Torit

Euxerus erythropus
leucounbrinus

Dec
2
Kapoeta
Lepus capensis subsp.

Apr
1
Jebel Kathangor Crocuta crocuta subsp.

Dec
1
Torit

Genetta tigrina aequatorialis Dec
2
Torit
Canis aureus soudanicus

Dec
2 3
Torit
Canis aureus soudanicus

Apr
5 1
Kapoeta

Herpestes sanguineus
sanguineus

Apr
3 52 Boma Plains Syncerus caffer aequinoctialis Dec
Holo

Syncerus caffer aequinoctialis Mar 1 Koss Valley Syncerus caffer aequinoctialis Jan 2 9 Laboni

Syncerus caffer aequinoctialis Feb 16 Torit

Syncerus caffer aequinoctialis Jan
3 4 Kapoeta

Hippotragus equinus bakeri Dec
1
Lafon

Hippotragus equinus bakeri Dec
1 Torit

Hippotragus equinus bakeri Apr
1 Torit

Hippotragus equinus bakeri Jan
Jebel Kathangor Gazella granti brighti

Dec 2 2 3 Torit

Sylvicarpa grimmia roosevelti Feb (2) 1 Torit

Rhynchotragus guentheri
smithii

Dec
15
Torit

Rhynchotragus guentheri
smithii

Apr
1
Lokila

Ourebia ourebi aequatoria Feb
1 I 1 Torit

Alcelaphus buselaphus
roosevelti

Apr
8
Loronyo

Alcelaphus buselaphus
roosevelti

Jan 7 1 1 Loronyo

Taurotragus oryx
patter sonianus

Jan

[graphic]

WNO

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