110 
AiSHSTALS OF THE TRANSVAAL MUSEUM. 
MARGAROPUS ANNUL AT US, var. AUSTRALIS, {FULLER). 
Rhipicephalus australis , Fuller (1899). 
Rhipicephalus annulatus, (Curtice), yar. australis, (Fuller), (Neumann,. 
1901, 1904). 
Margaropus annulatus, (Curtice), yar. australis, (Fuller), (Neumann, 1907). 
Plate VI, figures p to s. 
Male (VI, p, q) differs from decoloratus as follows : — A little smaller, 
more regularly oyal in outline, less contracted in front * hairs much more 
abundant, bio indications of caudal festoons ; caudal prolongation small 
and conical, sometimes wanting ; hypostome with eight rows of teeth 
mandibles with transverse process of inner apophysis tricuspid, (TT, r) ; 
spines of coxae I more deeply separated ; articles of legs relatively more: 
slender ; oval stigmatic plates not pointed on caudal extremity. 
Female differs from decoloratus as follows : — Slightly smaller when en- 
gorged, tending to a globose form and not elongate ; dorsal shield a third 
smaller and relatively wider, usually yellowish in the middle ; eyes not so- 
apparent. Rostrum very short ; mandibles as in male ; hypostome with 
eight rows of teeth. 
Hosts . — Same as decoloratus, cattle, horses, deer, buffalo, etc. 
Distribution. — Australia, Borneo, Sumatra, Singapore, and southern 
districts of Cape Colony. 
Lounsbury mentions this tick as occurring in the south-east districts, 
of the Cape Colony, very commonly on cattle. There was some doubt in my 
mind as to whether it was really australis or not, until I received some- 
specimens from Kingwilliamstown, C.C., along with decoloratus. They 
certainly conform to the characters given for australis. This variety also- 
transmits redwater of cattle. M. annulatus is an American species, and 
was first described in 1821 by Say as Ixodes annulatus. Since then there 
has been a difference of opinion by various workers as to whether this, 
species should belong to the genus Rhipicephalus, or form a separate genus 
by itself. In 1891 Curtice proposed to form a genus Boopliilus for its 
reception. This was adopted by most American authors, but when 
Neumann prepared his “ Revision de la Famille des Ixodides ” (1907), he 
placed it in genus Rhipicephalus, considering that the characters were 
not distinctive enough to form a separate genus. He, however, gave it 
the rank of a sub-genus, so that Rhipicephalus was composed of the sub- 
genera E uripicephalus and Boophilus. In 1906, however, he received some 
specimens of a tick from South Africa, the characters of the males 
of which were very peculiar, but the females of which were so similar in all 
essential characters to those of R. annulatus that he came to the conclusion 
that these two species were worthy of being raised to a separate genus, and 
called it Margaropus. 
In various parts of the world there are ticks closely resembling; 
annulatus, so much in fact that they are distinguished with difficulty and 
were once thought to be identical with annulatus. In each case these ticks 
transmit Texas fever, or redwater. 
