Female characters may be difficult to determine satisfactorily in greatly engorged, preserved specimens. Coxa I has two welldefined spurs discernably separated by a narrow but deep, inverted V-shaped cleft. Palpal segment one ventrally has an internal knob bearing one or two bristles; these bristles may be broken or obscured by crowding in preserved, engorged material. The scutum rarely may be approximately as broad as long, but more commonly is slightly longer than broad; the scutal margin, anterior of the eye, curves very slightly outwards. The hypostome formula is as in the male. Engorged individuals may reach 12.0 mm. or more in length and about 8.0 mm. in width. The normal slatish color of the engorged female and the blue of the nymph gives this tick its common name. Most specimens in my collection contrast with the usually paler females of the other two boophilids. Figure 116, B. decoloratus, ventral view (Sudan). Figure 117, B. annulatus, ventral view (Sudan). Figure 118, B. microplus, ventral view (N. Rhodesia). Figure 119, dorsal view of same species. DIFFERENTIATION OF BOOPHILUS FEMALES PLATE XXXVII 318 NOTES ON BOOPHILUS MICROPLUS (Canestrini, 1888) (= B. FALLAX Minning, 1934). (Figures 112 to 115 and 118) THE PANTROPICAL CATTLE TICK According to current concepts, the three Boophilus species of the Ethiopian and Malagasy Faunal Regions are the only ones known to comprise this genus throughout the world and subspecific designations are of questionable accuracy. The identification of the se species has been much confused in literature. The single species not yet known from the Sudan, B. microplus (= B. fallax), threatens to encroach upon these borders, therefore succinct notes on this latter tick are interpolated in spite of the general practice of excluding non-Sudanese species from this report. As elucidated below, it is impossible to differentiate so called diagnostic differences between specimens from African popu lations of B."fallax and specimens of B. microplus from popula tions in the Near and Middle East, various parts of Asia, and South America. Lengthy study of long series of material from these areas causes me to agree with Anastos (1950) that all these populations appear to represent a single species. On the other hand, Theiler reports (correspondence) that not only can she distinguish between B. fallax and B. microplus, but students with only basic knowledge of tick identification easily separate both species when presented as unknowns to be keyed! This matter is one of the very few items concerning which agree ment has not been reached with Theiler, after an extended exchange of notes and ideas. Theiler states (correspondence) that in her experience in the more southerly parts of Africa, B. "fallax" is usually local ly restricted, but where it does occur it is frequently numerous. There is a generalized, vague impression among students of the African fauna that B. fallax is an endemic Madagascan tick that has been introduced into Africa. However, the predilection of the Boophilus ticks for ruminants, absent in the endemic Madagascan fauna, as well as the apparently slow evolution of boophilids would appear to negate any possibility that the species may have evolved there within the few centuries that cattle have been introduced to these islands. It seems more likely that cattle from southern Asia brought their characteristic ticks with them to Madagascar. For over half a century there have been periods of heavy importation of Madagascan cattle into South and East Africa, and these probably introduced this tick into Africa. Export of cattle from infested African areas to Madagascar may have returned some ticks to the areas of their immigrant ancestors. DISTRIBUTION "B. microplus is found in Central America, South America, Australia, the Oriental Region, in the southern part of Florida, and in parts of Africa After examining specimens of B. fallax Minning from South Africa ....... I am convinced that this species is a synonym of microplus" (Anastos 1950). The following are selected records from the Ethiopian and Malagasy Faunal Regions for "B. fallax". EAST AFRICA: UGANDA (Wilson 1948A,1950C). TANGANYIKA (Minning 1934. Theiler and Robinson 1954). SOUTHERN AFRICA: MOZAMBIQUE (Theiler 1943B. Santos Dias 1953B, 1954H,1955A). NORTHERN RHODESIA (Matthysse 1954. Theiler and Robinson 1954). SOUTHERN RHODESIA (Theiler and Robinson 1954). NYASALAND (Wilson 1946,1950B. Theiler and Robinson 1954). UNION OF SOUTH AFRICA (As B. australis: Fuller 1899 and Lounsbury 1905. As B. annulatus: Donitz 19103. As Margaropus annulatus australis and as B. microplus: Howard 1908. Minning 1934. Theiler 1943B. Theiler and Robinson 1954). MALAGASY REGION: MADAGASCAR (Minning 1934. Bück and Metzger 1940. Bück and Ramambazafy 1950. Bück 1935,1948A,C. |