The number of longitudinal files of denticles on each side of the hypostome is expressed by a formula such as 4/4 or 3/3. The number of these files is constant in most species of ticks, but the number of denticles in each file may be more variable. The formula 3.5/3.5 indicates that there are three complete and one shorter file of few denticles anteriorly on each side of the hypostome.

Following Minning, the length/width ratio of the female scutum has usually been considered to be an important diagnostic character. Examination of large numbers of field collected specimens from Africa and elsewhere reveals wide variation in this feature within each species and no valid data for diagnostic purposes.

Figures 104 and 105, o, dorsal and ventral views Figures 106 and 107, Q, dorsal and ventral views

BOOPHILUS ANNULATUS (Say, 1821) (= B. CONGOLENSIS Minning, 1934).

In addition to the above Equatoria Province specimens, the following others have been seen, all from cattle except those which were collected at Wau from donkeys:

Dec 1926

J. W. Cowland (SGC)

3

Wadi Halfa Quarantine Station from Kordofan cattle (SGC)

The Sudan distribution picture is a curious one. Although we have a fair number of collections from cattle in that half of Equatoria Province that is east of the Nile, none contain specimens of B. annulatus except two from high altitudes (lo from Katire, 3500 feet elevation, lo from Nagichot, 6500 feet eleva tion) and one from Torit, at the general two thousand foot level of the plains in this area. Yet collections from the southern part of Upper Nile Province, which is just north of the east bank of Equatoria Province, include a good number of specimens. Cli matic, faunal, or floral differences can hardly account for the rarity of B. annulatus in Torit and Juba districts. The most easterly record, Akobo, Upper Nile Province, is on the Ethiopian frontier (747 N., 33°01'E.). On the west bank of the Nile, this species is here recorded from several localities to as far north as Talodi, Kordofan Province (10°37'N.).

Some specimens reach the Halfa Quarantine station in Northern Province but Boophilus ticks have never been collected from indige nous cattle in Northern Province.

DISTRIBUTION

Thus far we know B. annulatus only from West Africa, Central Africa, and certain parts of southern Sudan near the periphery of East African biotic Provinces. As early as 1905, Dönitz recognized that this tick inhabited only "tropical Africa" and was absent in eastern and southern Africa. He tentatively applied the name B. australis Fuller to it, although he stated clearly that he could not differentiate African material from descriptions of American B. annulatus. Unfortunately, he had no American specimens for comparison for it appears that this perspicacious student might otherwise have saved future generations much misunderstanding. Instead, this species subsequently has been either completely overlooked or subjected to numerous ambiguous remarks and names.

Many African specimens undoubtedly have been identified as B. decoloratus, and earlier workers who have recognized specimens as different from B. decoloratus have referred to them by various names. The actual species with which various investigators were dealing cannot be determined without seeing their specimens. For instance, Nuttall's lots identified as B. australis, which have

been examined in British Museum (Natural History), contain both B. decoloratus and B. annulatus.

B. annulatus is a North American cattle tick that one may assume originally parasitized deer and buffalo. It also has been introduced into the Mediterranean basin. In North Africa and the Near East, it frequently is referred to as B. calcaratus (Birula, 1894), to which Minning appended several subspecies. These all appear to be the same as American and African populations of B. annulatus. The name also has been used by students of the Oriental fauna but examination of pertinent specimen material is indicated to establish the validity of these identifications.

Records presented below are the only ones from Africa that are known to pertain to B. annulatus, with a few additional, an notated references that might be pertinent. Quite possibly other isolated populations are maintaining themselves outside of the presently recognized range of the Texas fever tick in the Ethiopian Faunal Region, having been introduced on cattle from West or North Africa, the Near East, or North America.

WEST AFRICA: NIGERIA (Hoogstraal 1954C). LIBERIA (Specimens from cattle at Harbel, Firestone Rubber Company Plantation, H. A. Beatty legit; MCZ collections). SIERRA LEONE (Hoogstraal 1954C). PORTUGESE GUINEA: B. (= Margaropus) annulatus listed by Monteiro da Costa (1926) and Sant'anna Barreto (1929); quoted by Tendeiro (1951A), but not subsequently repeated in faunal lists by this author although it would not be surprising to find this tick here.7

NOTE: Records below are for "B. congolensis".

CENTRAL AFRICA: FRENCH EQUATORIAL AFRICA (Minning 1934. Rousselot 1953B. Theiler and Robinson 1954). CAMEROONS (Rageau 1953A,B). BELGIAN CONGO (Theiler and Robinson 1954. Minning 1934 stated, apparently as a guess, that the B. annulatus calcaratus specimens of Newstead, Dutton, and Todd 1907, from Coquilhatville, are "B. congolensis").

EAST AFRICA: SUDAN (Hoogstraal 1954B,C. Balfour 1911F referred to "B. australis" in the Sudan, but since he also stated that B. decoloratus is absent there his remarks are difficult to interpret).