Plague: R. s. sanguineus does not appear to play a role in the natural transmission or preservation of Pasteurella pestis, although it is claimed that the subspecies schulzei has been found naturally infected.

Tularemia: Bacterium tularense survives from the larval to adult tick and may be transmitted by any stage.

Toxoplasmosis: Toxoplasma gondii acquired by immature stages feeding on an infected host may be retained during the later devel opmental stages of the tick. There is some possibility of trans ovarial infection but this has not been definitely proven. Results of experiments in these respects by various workers are contra dictory. The probability of natural transmission remains unknown.

Kala azar:

Leishmania donovani survives in the kennel tick but can be transmitted only experimentally.

Chagas disease: R. s. sanguineus may mechanically transmit Trypanosoma cruzi.

Experimental (Animal Diseases and Syndromes)

Tick paralysis: See above.

Toxoplasmosis: See above.

Guineapig pneumonia ("pneumopathie du cobaye"): The kennel tick is not a vector of the causative virus of this disease.

Equine piroplasmoses: R. s. sanguineus is a vector of both Babesia caballi and Nuttallia equi.

Rodent piroplasmoses: Circumstantial evidence indicates that this tick may transmit Piroplasma quadrigeminum of the gondi. This tick transmits a benign uttallia (?sp.) to jirds, Meriones tristrami.

Tropical theileriasis: It is said that this tick is a vector of Theileria annulata of cattle.

East Coast fever: R. S. sanguineus does not transmit Theileria parva of cattle.

Anaplasmosis: Gallsickness, Anaplasma marginale, of cattle is carried by the kennel tick.

Redwater: R. s. sanguineus may be a vector of Babesia bigemina of cattle.

Trypanosomiasis: The causative organism of surra, Trypanosoma evansi (■ T. annamense), dies quickly in this tick, and that of an African trypanosomiasis, T. congolense, is not transmitted by it. Another flagellate, Crithidia christophersi, has been reported to occur in the kennel tick.

Rabies; Tompkins (1953) compares textbook statements that rabies is not transmissible by arthropods to saying that the aard vark is immortal because nobody has seen a dead one. He failed to become more rabid than this after serving as a host for a kennel tick that almost certainly had previously fed on a rabid fox. More than this nobody knows concerning rabies and ticks.

Rodent Cestodes: The mouse tapeworm, Hymenolepis microstoma, is said to be transmitted by this tick.

Canine Filariasis: The canine filaria, Dipetalonema grassii, is said to be transmitted by the kennel tick, which may also trans mit Dirofilaria immitis and, questionably, Dipetalonema reconditum. So far as known, the role of R. s. sanguineus in the transmission of these parasites in nature has not been elucidated.

Salmonella: In dogs and laboratory animals; see Logs above.

Experimental (Miscellaneous)

Mistaken Identity: Cryptoplasma rhipicephali Chatton and Blanc (1916A), grouped with the haemogregarines, was indicated by the same authors (1916B) to be really the tick's spermatozoa.

REMARKS

Taxonomy

In his generic revision of Rhipicephalus, Zumpt (1950A) considers R. sanguineus as a group of subspecies, which, besides

the typical form, includes the subspecies sulcatus Neumann, 1908, of Africa, and both rossicus Yakimoff and Yakimoff, 1911, and schulzei Olenev, 1929, of Russia. R. sulcatus, now considered as a distinct species, is treated separately in the present study. The Soviets (Pomerant zev 1950) consider the Asiatic forms also as distinct species and add the following related species: R. turanicus Pomerantzev, 1940; R. pumilio Schulze, 1922; R. leporis Pomerantzev, 1946; and R. schulzei Olenev, 1929.

Owing to the obvious difficulty of an independent evaluation of Soviet species, Zumpt's (loc. cit.) terminology is utilized in the present report. However, a survey of our own material from the Near East and ecological observations leave us, at present, uncertain over which of these two schools of thought is the correct one.

More recently, Feldman Muhsam (1952A) has designated as a very closely related species, R. secundus, distinguishable from R. s. sanguineus only by the form of the female genital aperture and of the capitulum of larvae and nymphs. Although Feldman Muhsam's reared material shows these differences, Mr. Kaiser and I have been unable to distinguish R. secundus after weeks of study of a very considerable number of kennel ticks from tropical Africa, North Africa, Arabia, and the Near East. Feldman Muhsam (1953) did not recognize R. secundus in American specimens she studied, but claims to have found it among materials from Palestine, Turkey, Yugoslavia, France, Algeria, and French West Africa (and un published - Yemen and Egypt). Specimens identified as R. secundus by Feldman Muhsam have been reported from Iraq along with R. s. sanguineus (Hubbard 1955).

It appears obvious that full understanding and agreement of the status of subspecies and species related to R. sanguineus awaits more refined laboratory and field techniques than have yet been accorded this problem; possibly a more advanced con sideration of species criteria and of taxonomic tools than have yet been applied to ticks; and freer exchange of ideas and intercourse in presently antagonistic regions of the world.

It will be noted in the section on IDENTIFICATION, below, that an important diagnostic criterion for this tick is the

presence of a scutal pattern of punctations arranged in four more or less regular longitudinal rows. This characteristic defines the R. simus group and it is suggested (page 751) that R. s. sanguineus might logically be considered as a member of the same group.

Structure and Physiology

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). See also Lombardini (1950).

The integument and sections of the scutum have been illus trated by Schulze (1943B), who also mentioned the color of the gut contents.

Water balance studies of various ticks, as discussed for 0. moubata (page 153), reported by Lees (1946A), include the observation that R. s. sanguineus falls in about the middle of the range among the species studied with respect to its power of limiting evaporation. Variations in this capacity may reflect specific differences in the nature of the epicuticular lipoid among these species. See also Lees (1947).

Teratological (malformed) specimens have been occasionally reported. Warburton and Nuttall (1909) illustrated a Gold Coast specimen with duplication of the posterior parts of the body. Nuttall (1914A) described asymmetrical specimens and others lacking one leg. Sharif (1930) also noted absence of legs. Others have been described by Sharif (1930) and Pavlovsky (1940). These reports have been incorporated in an overall review of the subject by Schulze (1950B). Posteriorly joined adanal shields were illustrated by Santos Dias (1955A). A remarkable larva in which one of the palps appears to be partially converted into a typical leg has been described and illustrated by Pavlovsky (1940) and reviewed by Campana (1947).

A gynandromorph has been described by Pereira and de Castro (1945). It is somewhat interesting, in view of the considerable

attention devoted to this subject and to teratological specimens in some schools, that no other such observations concerning this common and widely ranging tick have been reported.

Tick feeding from tick: A male with its mouthparts inserted in the integument of an engorged female has been described by Sharif (1930). In Egypt we observe that males of various tick species insert their mouthparts into the female body cavity when the latter is engorged and both are confined in tubes for several days after having been collected. This is especially common among specimens of B. annulatus B. calcaratus).7

Comparative measurements ("allometrie") of sexual variations among the Ixodidae have been investigated by Chabaud and Choquet (1953). For the kennel tick, the length of the adanal shields and the spiracular plates in relation to the tick's length is logarithmically illustrated. Because of sexual and nutritional dimorphism, these authors consider ticks as important biometric tools. They also believe that certain cases of intersexual ticks may result from nutritional allometry. If a male structure is similar to that of a female it has an isometric growth, but if different an allometric growth.

Variation in body size and morphology parallels that already discussed under R. appendiculatus (page 614) and the same comments apply. This subject has been studied by Cunliffe (1914A) and Pervomaisky (1954). See also remarks under IDENTIFICATION, below.

Growth and increase in size from stage to stage and with adult engorgement has been noted by Campana-Rouget (1954).

Internal anatomy was briefly described and diagrammatically illustrated by Regendanz and Reichenow (1941).

Haller's organ of this tick (= R. macropis) has been illus trated by Schulze (1941).

Oviposition and the larva have been described by Samson (1908). Included in this report is a sketch of the female laying eggs, a generalized discussion of the subject, and a short des cription of the morphology, including the internal organs (illus