Cordurier, Bück, and Quesnel 1952. Hoogstraal 1953E. The B. "caudatus of Colas Belcour and Millot 1948 may refer to this species. Minning 1934 refers all reports of B. decoloratus from Madagascar and other islands in this group to B. microplus (= B. fallax). It appears that B. decoloratus has not established it self in this archipelago). MAURITIUS (De Charmoy 1915. and Mamet 1947. Millot 1948. Hoogstraal 1953E). REUNION (Gillard 1949. Hoogstraal 1953E. The "B. caudatus" reported by Neumann 1897 may refer to this species). COMORES GROUP (Minning 1934. Millot 1948. Hoogstraal 1953E). SEYCHELLES (Desai 1952).

butia

HOSTS

All authors report domestic cattle as the chief host. Minning (1934) also noted specimens from a domestic horse and Theiler (1943B) from domestic sheep and goats. Bück (1935,1948A,C) found material on domestic sheep and Buck and Ramambazafy (1950) on domestic horses. The only wild animal known to have served as a host in Africa is a lion (Theiler 1943B).

Anastos (1950) reports chiefly domestic cattle but also a variety of other domestic animals as hosts of B. microplus in Indonesia. He noted that records from wild mammals and birds and from domestic chickens are extant.

BIOLOGY IN ETHIOPIAN AND MALAGASY FAUNAL REGIONS

Life Cycle

This is a single host tick. Engorged females leave the host from 35 to 149 days after having attached as larvae, and there may be from two to three generations a year in South Africa (Lounsbury 1905).

Wilson (1946) observed no seasonal periodicity of adults in Nyasaland. He found larvae with nymphs and adults on cattle only once. Nymphs and adults were usually found together. Nymphs and adults are almost constantly restricted to the udders, flanks, and belly; larvae to the inner side of the ears of the host.

Elsewhere, a number of biological studies on this species have been reported. Among these are Sapre (1940) for high altitudes in India, Tate (1941) for Puerto Rico, Legg (1930) for Australia.

Ecology

As already stated, B. microplus occurs only locally in Africa but where present it may be very common. In Northern Province of Nyasaland it is more numerous on cattle than B. decoloratus (Wil son 1946). In the Malagasy Region, B. microplus is largely a lowland species with scattered foci around urban highland localities (Bück 1948A,C). In Africa it survives best in natural forest conditions (Theiler 1943B).

Early in the century, the range of B. microplus in eastern and southern Africa was wider than it now is, probably because of more frequent importation of infested cattle from Madagascar at that time. Climatic conditions have reduced these populations to their present more localized foci (Theiler 1943B) but exten sions of these infestations should be anticipated. This tick was introduced into southern Africa after the 1896 rinderpest outbreak (Theiler and Robinson 1954).

REMARKS

A misshapen specimen has been described and illustrated by Santos Dias (1955A). My collection contains two gynandromorphs.

The synonymous B. australis Fuller, 1899, was described in South African literature. Fuller also gave a differential diagnosis for the three forms presently recognized as comprising this genus.

DISEASE RELATIONS

Unstudied in Africa. The following references are for the Americas, Asia, and Australia.

Cattle: Redwater or Texas fever (Babesia bigemina). Babesiosis (Babesia berbera). Anaplasmosis or gallsickness (Anaplasma marginale).

Sheep: Babesiosis (Babesia ovis).

Horses: Biliary fever (Nuttalia equi).

Wherever and under whichever name it occurs, this tick appears to be of considerable veterinary importance.

IDENTIFICATION

Male: This small, yellowish to reddish brown tick varies from about 1.6 mm. to 2.5 mm. in overall length, and from 1.0 mm. to 1.4 mm. in width. The presence of a short, tapering caudal append age is noteworthy (absent in B. annulatus, present in B. decoloratus, but in B. microplus the interno posterior juncture of the adanal shields does not extend beyond the posterior body margin). The hypostome dentition is 4/4 (typically 3/3 in B. decoloratus); and the inner margin of the basal palpal segment ventrally is concave (bearing a bristle-bearing protuberance in B. decoloratus). The scutum is quite hirsute.

Minning (1934) indicated, as his primary critical difference between B. fallax and B. microplus, the bluntness or acuteness of the inner spur of coxa I. This character is variable among specimens from Africa and other continents; figure 112 illustrates a specimen from Northern Rhodesia in which this spur is blunt on one side and acute on the other!

Female: After some experience females should be easily recognized in African collections, provided one carefully and methodical ly observes clean specimens from which the wet surface film of preservatives has been removed.

Like that of B. annulatus, this sex has 4/4 hypostome dentition. B. microplus can be distinguished because the spurs of coxa I are divided by a deep, inverted "V" shape cleft, while those of B. annulatus are separated merely by a shallow, concave emargination (this character should be ascertained by placing the specimen obliquely against the light). No bristle-bearing pro

tuberance is found on the inner margin ventrally of the basal pal pal segment. The inner margin of the basal segment is short and deeply concave by comparison with that of B. annulatus. The palpi usually appear more compact and less acutely ridged.

Minning's (1934) character for separating B. microplus and B. fallax on the basis of the anterior curvature of palpal segment 3 applies only to his illustrations, not to specimens. The scutum, normally slightly longer than wide, may be widened by engorgement (from 0.40 mm. to 0.58 mm. long and from 0.34 mm. to 0.50 mm. wide). The eyes are generally oval and raised above the scutal surface but this character may be difficult to discern. Size varies from about 2.0 mm. to 12.5 mm. long, and from 1.0 mm. to 7.9 mm. wide, depending on degree of engorgement.

DERMACEN TOR

INTRODUCTION

Dermacentor, a medically important genus in many parts of the world, is represented by only three species in tropical Africa. Small populations of two of these, D. c. circumguttatus and D. rhinocerinus, occur in Equatoria and Bahr El Ghazal Provinces of the Sudan. In Africa they are always rather rare and largely con fined to the rhinoceros and elephant. As such, they are of little more than academic interest. The identity of these species may be determined easily from the following keys and illustrations.

The third African species, D. hippopotamensis (Denny, 1843) Ixodes bimaculatum Denny, 1843, and Amblyomma hippopotami Koch, 1844), was originally described from Hippopotamus amphibius of South Africa. Schulze Schulze (1919) erected the genus Cosmiomma for this species on the basis of its Hyalomma like characters although it lacks accessory shields and subanal shields. Zumpt (1951) sank Cosmiomma under Dermacentor but Theiler states (correspondence) that Schulze's definition justifies its retention as a genus. Other authors have placed it in Hyalomma. Still another study by a qualified student on the original material appears necessary be fore an acceptable systematic niche can be found for D. (C.) hippopotamensis.

D. (C.) hippopotamensis has been reported from South Africa and between "Zanzibar (i.e. East Africa) and the Great Lakes (Tan ganyika). For over a century, the only positively known specimens have been the types described by Denny and by Koch, which have been seen again by later students. In the collections of the East Afri can Veterinary Organization there is a single male taken from vege tation at Manyani, Teita District, Kenya, 5 November 1951, D. L. W. Sheldrick legit. This specimen, according to J. B. Walker (correspondence), is almost exactly like the type material illustrated by Dönitz (1910B). One or two specimens are in the collection of the Veterinary Department at Kabete, Kenya.

D. (C.) hippopotamensis is a large, brightly colored Amblyomma like tick. The male scutum is described as pale straw-yellow with symmetrical black markings and a few small punctations; ventrally