the same unique ecological zones due to movements of wild hosts or of domestic hosts. They are sympatric species in which hybridiza tion is not known to occur. The highland range of R. compositus is confirmed by the care ful study of numerous records by Theiler, Walker, and Wiley (1956). Sudan specimens from a buffalo near Nimule, which is a savan nah area at the level of the Nile River, 2,059 feet elevation, might appear to be exceptions to the highland concept of this species. They were, however, collected in December, shortly after the end of the rainy season, when there is a tremendous movement of outlying animal populations towards the river. It seems prob able that the buffalo from which these ticks were taken had re cently come to the river from the nearby Acholi mountains, where he had acquired these parasites. In Nyasaland, adults were collected only in December and Jan uary (middle rainy season), when adults of the closely related R. capensis were absent (Wilson 1950B). Matthysse (1954), working in Northern Rhodesia, considers it noteworthy that adults of R. compositus preceed those of R. appen diculatus, being found abundantly before the rains, in September and October, and also being present in July, August, and November. Rains commence in November. This factor may be of importance in the transmission of East Coast fever during the absence of adult brown ticks. "Cattle examinations during the latter part of the dry season and during the early rains will show many brown ticks on the undersides of the body, in the tail brush, and on the feet, but not in the ears. These ticks are largely R. compositus" (= R. ayeri) (Matthysse 1954). The same author lists a single collection from the ears of cattle. DISEASE RELATIONS CATTLE: A vector of East Coast fever (Theileria parva). REMARKS The confusion regarding the taxonomic position of this spe cies is reviewed in detail by Theiler, Walker, and Wiley (1956) in a report so easily available to all specialists who might be concerned with this matter that it is not abstracted here. These authors, with admirable conservatism, persist in referring to that tick herein called R. compositus by the name R. ayeri. However, their various rearing and distributional studies show R. ayeri to include all morphological and ecological features of R. capensis compositus and to be a valid species and taxonomic entity, separate and distinct from R. capensis, which they have also reared through the F1 generation. They say: "As to whether R. ayeri is R. compositus or not, we are inclined to think that it is, but we are at the moment not in a position to commit ourselves". In their summary, it is stated that: "(R. ayeri) is shown to be a valid species and is in all probability synonymous with Neumann's 1897 R. compositus". While there is some possibility that eventually R. compositus and R. ayeri will be shown to be separate species, this at present appears so unlikely that I, more rashly than my friends, am calling this material R. compositus. Santos Dias (1948A) attributed a slightly misshapen specimen to R. ayeri. The Sudan material has been checked by Dr. Theiler. IDENTIFICATION Males: Size medium to large (4.00 mm. to 7.75 mm. long). Scutal punctations are numerous, very closely spaced, but mostly noncontiguous, uniformly large in central area (in R. capensis, large punctations are scattered among numerous smaller punctations in central area), fewer or absent bordering at least the anterior half of the lateral grooves. The cervical area may have somewhat more variable punctations within lateral grooves (few in R. capensis). Cervical pits are short and deep; cervical grooves are shallow, diverging (frequently indistinct) (deep and long in R. capensis). The body margin is regularly rounded or slight ly bulging posterior of the eyes*. Lateral grooves are deep, extending from usually clearly-marked pseudoscutum to margin between second and third festoon. The posteromedian groove is long and narrow (possibly wider and sometimes shorter in R. capensis); paramedian grooves are narrow. A small dorsal hump of coxa I is visible. The basis capituli is nearly twice as wide as long; lateral angles are at the basal third and acute. The color is dark brown (usually light brown in R. capensis) to black. Adanal shields are of the widely triangular type with rounded junctures and margins and a slightly emarginate inner margin. The wide, glossy scutal periphery and the numerous, regular scutal punctations are striking. Females: This sex has a similarly wide, glossy border of the dark brown or black scutum, with but few, small punctations outside the definite lateral grooves, which extend the full length of the scutum. The scutum is, therefore, quite distinctive. This feature, together with the rounded scutal margin (sometimes slightly indented posterior of the eye), numerous, uniformly large punctations in the central field and a few small punctations anteriorly, and scutal length (only slightly wider than long) rather easily separates R. compositus from the female of R. capensis (which has punctations reaching the lateral scutal margin, slightly greater scutal width, and numerous small punctations irregularly scattered among fewer large punctations). Cervical grooves are short and deep. Females are about 7.5 mm. long and 5.0 mm. wide, scutum about 2.2 mm. long, and 2.3 mm. wide. Note: In the Sudan tick fauna there should be little dif_ ficulty in determining R. compositus. The criteria separating this species from R. capensis have been included above because of the *According to Santos Dias (1949F) the body outline of R. capensis bulges more than in R. compositus (= R. ayeri) just posterior of the eyes. This is not necessarily true in nonrobust specimens. possibility that this important species may some day be introduced into the Sudan. This is the only Sudanese species in which the male scutal punctations are large, deep, dense and noncontiguous centrally, the margins are wide and glossy, and the posterior grooves are narrow. The dense, uniform female scutal punctation, the glossy, smooth scutal periphery, and the wide, regular scutal outline easily distinguishes this sex in the Sudan fauna. |