94 
Annals of the Transvaal Museum. 
Females. 
A . Anal grooves converging behind the amis, but not joining. 
B. Dorsal shield as wide as long ; anal groove with branches 
not so close together at posterior end ... ... pilosus * 
BB. Dorsal shield longer than wide ; anal groove with 
branches closer together at posterior end 
pilosus howardi . 
AA. Anal grooves parallel behind the anus... rubicundus. 
IXODES PILOSUS, KOCH. 
Sheep Paralysis Tick. 
Ixodes pilosus, Koch (1844, 1847). 
Ixodes pilosus, Koch (leiimann, 1899). 
Male. — Body oval; wider and rounded behind; length 3.15 nun.; 
width 1.6 mm. ; colour clear reddish brown. Shield convex, covering 
all the dorsal surface, except a narrow marginal cushion, which is 
lighter coloured, shining, glabrous; cervical grooves of the normal 
length, well formed, punctuations very fine, abundant. Ventral 
surface with genital pore wide, opposite coxae III; pregenital shield 
trapezoidal ; anal shield small, longer than wide, sides curved and 
converging like a horseshoe ; anus with three hairs on each valve. On 
all the surface of the body many hairs, those on the ventral surface 
short and translucent, those on the epimeral shields reinforced at the 
base. Rostrum elongate ; base twice as wide as long, in shape of a 
trapezoid opening in front on the dorsal surface, a little longer than 
wide on the ventral surface,, where it is pentagonal in outline ; 
mandibles with inner apophysis of digit applied to the dorsal surface 
in the anterior, where it has the appearance of being doubled ; three 
teeth, the terminal small, the median one strong, and the basilar one 
weak, the outer apophysis with seven or eight teeth, the anterior ones 
progressively decreasing, and forming a crest, the posterior ones very 
strong ; hypostome with a marginal series of six to eight teeth on each 
side, increasing in size from top to base ; the remainder of the teeth 
are reduced to single transverse crenulations ; palpi compressed from 
top to bottom, dorsal face flat, ventral face excavated, hairs scattered 
over the dorsal surface, in series on the inner margin. Legs slender; 
coxae elongate, coxae I with a strong spine on the postero-median 
edge ; hairs on all the articles of the legs ; tarsi slender, forming in 
leg I about a quarter of the length of the leg. 
Female.- — When unengorged, body hat, oval in outline, much 
wider and rounder behind ; colour yellowish red ; long whitish hairs 
on all the surfaces ; when engorged resembles a castor-oil bean, slightly 
battened, and becomes of a dark bluish black colour. Shield yellowish 
brown, lighter than the abdomen when young, glabrous, oval, some- 
what pentagonal in outline, as wide or almost as wide as long ; 
posterior lateral margins almost straight ; cervical groove pronounced, 
reaching the posterior margin ; lateral grooves well marked, and 
reaching the posterior margin ; punctuations very fine, equal on all 
the surface ; a few short, whitish hairs ; integument with a few hue 
