Annals of tfie Transvaal Museum, 
107 
MARGAROPUS ANNULATITS, var. DECOLORATUS, 
{KOCH). 
The Blue Tick. 
Rhipicephalus decoloratus, Koch (1844, 1847). 
Rh ip icephalus decoloratus , Koch (Neumann, 1897). 
Rhipicephalus annulatus, (Curtice), var. decoloratus, (Koch) 
(Neumann 1901, 1904). 
Maf gar opus annulatus, (Curtice), var. decoloratus , (Koch) (Neumann 
1907). 
Plate VI, figures a to o. 
Male. — Body oval, narrowed in front, presenting its greatest 
width (1.0 to 1.5 mm.) at the level of the stigmatic plates, length 
2.0 to 2.75 mm. ; integument very thin, often allowing the ramifica- 
tions of the intestines to show through. Shield (VI , a) reddish brown, 
covering all the dorsal surface, prolonged on each side of the rostrum 
in front by two horns, the inner of which is smaller ; two cervical 
grooves, shallow and wide, extending to the posterior margin, 
interrupted in the middle and widened into a shallow pit at its 
resumption ; a median groove in the posterior half, posterior festoons 
scarcely marked, except the median ones, which are indicated by 
scallops ; punctuations large, superficial ; numerous short hairs 
scattered all over the shield, which is finely wrinkled ; eyes pale, very 
small, often almost invisible, at level of first inter-coxal space; dorsal 
porose areas at posterior third of length, very small and well separated. 
Ventral surface (VI, b) same colour as dorsal, with numerous 
long, whitish hairs on all its extent ; sexual orifice wide, situated a 
little behind the level of the anterior margins of coxae II, a large 
triangular plate forms its posterior margin ; anus near posterior 
quarter of length ; on each side of the anus an elongate plate, 
extending forward as far as the posterior margin or middle of 
coxae IV, anterior end pointed, inner margin longer and prolonged 
into a conical point on posterior end ; posterior margin emarginate ; 
outside of each anal plate another much smaller and narrower, but 
of almost same shape as first ; both of these pairs of plates may 
extend beyond the posterior margin of the body; a strong conical 
caudal prolongation of the body' on the median line ; truncate on the 
tip and curved downward ; stigmatic plates almost circular, large. 
Rostrum (VI, c) very short, dorsal base hexagonal, wider than long ; 
lateral angles very sharp, inserted into a rather shallow emargination 
of the shield; ventral base semi-circular; mandibles (VI, /), with 
inner apophysis of digit, bearing a transverse process with two sharp 
teeth; outer apophysis with two teeth, the lower large and strong, the 
upper very small and sub-terminal ; hypostome short and wide, 
emarginate at tip, numerous denticles on anterior end followed by 
three rows of large teeth on each half ; palpi short, sub-conical, with 
articles as wide as long ; article I concealed in part under anterior 
dorsal margin of base of rostrum ; article II constricted at base, 
widened in middle into a prominent crest on both inner and outer 
margin ; numerous strong spines, especially on inner margin ; article 
