in small numbers in dry areas of the R. pravus A. gemma associa tion. The ecology of this tick requires further detailed investiga tion.

Around Mbui, Adamawa Province, Nigeria, the red tick forms sixty percent of the specimens in tick collections (Unsworth 1949). Reasons for this density should be interesting to investigate.

In the Sudan, the red tick is absent in true desert areas but does occur and is common in a wide variety of forested savan nah and semidesert areas.

In Moreau's (1933) study of ticks in the stomachs of the tick bird, Buphagus erythrorhynchus (Stanley) in Tanganyika, specimens of R. e. evertsi were found in three of 58 birds examined. They numbered one, six, and eighteen ticks per stomach. In Kenya, van Someren (1951) found three adult red ticks in the stomachs of two of the same kind of bird, but none were found in ten other of the same kind that he examined and none were found in stomachs of seven B. a. africanus. A further discussion of this subject is presented under A. variegatum, page 275. The concealed places in which the red tick usually feeds probably protects it from this predator except in special circumstances.

Nymphal R. evertsi removed from hares, Lepus zuluensis, have been found infected with the chalcid parasite Hunterellus hookeri Howard, 1908 (Cooley 1934, see also note by Bedford in Cooley 1929).

REMARKS

Integumentary sense organs, which are fixed in number and location, and which are essentially similar in all stages of the tick, though more primitive in larvae, have been described and illustrated by Dinnik and Zumpt (1949). This subject has also been discussed by K. W. Neumann (1942).

Preliminary studies on spermatogenesis by Warren (1931), which do not appear to have been completed, indicate that in R. e. evertsi a single spermatid gives rise to several sperma_ tozoa of extremely variable size. Warren's observations differ considerably from those of Nordenskiöld (1920) on Ixodes ricinus.

Misformed specimens of R. e. evertsi have been reported on by Santos Dias (1947B,1948A,1954H). An egg toxin has been found in this species (De Meillon 1942). Symbiotes have been reported and discussed by several workers: Cowdry (1923,19250,1927), Buchner (1926), and Jaschke (1932). The arch of the eye has been briefly mentioned by Gossel (1935). Dönitz (1905) observed copulation. by insertion of the male hypostome into the female genital aperture while the legs are used as clasping organs adjacent to the corresponding legs of the female but was unable to ascertain how seminal fluid was passed; Christophers (1906) stated that ob viously it is accomplished by transfer of spermatophores during the mating act.

The life cycle and morphology of the red tick are so peculiar within this genus that a special subgeneric niche might seem in dicated for R. evertsi. Theiler informs me (correspondence) that Dr. Cooley also entertained this idea while he was in South Africa, but that the immature stages are so normally rhipicephalid as to dampen any urge to take this step_7.

DISEASE RELATIONS

MAN: Boutonneuse fever (Rickettsia conorii).

CATTLE: East Coast fever (Theileria parva). Pseudo-east coast fever (T. mutans). Redwater (Babesia bigemina). Spirochetosis (Borrelia theileri). Not a vector of heartwater (Rickettsia ruminantium). A secondary bacterial infection by Corynebacterium pyogenes causes an otitis leading to the sloughing of the host's external ear when infested by larvae and nymphs. The virus of "a specific transmissible petechial fever of cattle" may be trans mitted to sheep by the red tick.

SHEEP: Lamb paralysis (?toxin). Apparently not a vector of Nairobi sheep disease (virus). See paragraph above.

HORSES, MULES, and DONKEYS: Equine piroplasmosis (biliary fevers) (Babesia equi and B. caballi). Spirochetosis (Borrelia

theileri

IDENTIFICATION

Males: The red tick is usually large (5 mm. long) though smaller specimens do occur. Its dark scutum contrasts greatly with the reddish body integument and saffron legs. The dark eyes are hemispherical, protruding, and orbited, similar to those of hyalommids but to no other rhipicephalids except R. oculatus (and, partially, to R. pravus). Scutal punctations are of medium and large size and so numerous as to cause the scutum to appear shagreened. Lateral grooves, a posteromedian groove, and para median grooves are pronounced. A large, painted process from coxa I is visible dorsally. The huge adanal shields, very wide and posteriorly semicircular in outline, are also unique.

Female:

This sex is colored as in the male and has similar scutal punctations and eyes so that it can never be mistaken. The scutum lacks lateral grooves.

The larva and nymph have been described and illustrated by Theiler (1943B).

Note: The subspecies R. evertsi mimeticus Dönitz, 1910 (B), has yellow ringed legs while those of the typical evertsi are unicolorous.

Figures 269 and 270, o, dorsal and ventral views Figures 271 and 272, o, dorsal and ventral views

PLATE LXXVI

-654

The Nagichot specimens, from a cow at 6500 feet elevation in the Didinga Mountains, were collected by Mr. H. B. Luxmoore in 1951. The British Museum (Natural History) specimens, found un identified in their collections, were taken by Mr. J. D. MacDonald in 1938 at Kipia, 8800 feet elevation, in the Imatong Mountains. The Weber specimens from the same locality, but reportedly at one hundred feet lower elevation, were identified (Weber 1948) as R. bursa. Weber's specimens, kindly loaned by Dr. J. Bequaert, were independently identified by Dr. Theiler and by me as R. kochi.

R. kochi is known in the Sudan only from the high mountains in the central part of the eastern half of Equatoria Province.

DISTRIBUTION

R. kochi, a tick of the more humid and temperate highlands of Central Africa, less commonly also inhabits the highlands of East Africa (see also Ecology of R. compositus, p. 625). Records previous to 1950 should be accepted with caution.

CENTRAL AFRICA: BELGIAN CONGO and RUANDA URUNDI (Schoenaers 1951A,B. Rousselot 1953B. Theiler and Robinson 1954. Van Vaerenbergh 1954).

EAST AFRICA: SUDAN (As R. bursa: Weber 1948. Hoogstraal 1954B).