106 Annals of the Transvaal Museum. 
be placed together in a separate genus. The name Mar gar opus was 
given to the genus because this name had been given by Karsch to a 
form from Chili prior to the proposing of the generic term Boophilus 
by Curtice in 1890. As it happened, the form which Karsch named 
( M . iventhemi) was a monstrosity, of one of the varieties of R. 
annulatus ; the legs of the male individual were very flat and dilated 
as in the male of lounsburyi ; but according to article 27, of Inter- 
national Rules of Zoological Nomenclature, Mar gar opus has the 
priority over Boopliilus, since it refers to the part of the species 
named first . * 
Males. 
A. Four anal plates, free in front of anus; legs sub-cylindrical. 
B. Hypostome with six rows of teeth ; anal plates pointed 
at posterior tips ; caudal appendage blunt, but always 
present ... ... ... ... annulatus decoloratus. 
BB. Hypostome with eight rows of teeth ; anal plates square 
cut at posterior ends ; caudal appendage small and 
conical, often absent ... ... annulatus australis. 
A A. Two anal plates, united in front of the anus; articles of 
legs very much dilated, articular angles deep... lounsburyi. 
Females. 
A. Articles of legs sub-cylindrical; spur short, ambulacre sub- 
terminal . 
B. Hypostome with six rows of teeth ; mandibles with lesser 
process bicuspid ... ... annulatus decoloratus . 
BB. Hypostome with eight rows of teeth; mandibles with 
lesser process tricuspid, centre of shield usually 
yellowish ... ... ... ... annulatus australis. 
A A. Articles of legs dilated at distal extremities; spur very long, 
ambulacre inserted at dorsal border of spur, remote from the 
tip ... ... ... ... ... ... ... lounsburyi. 
Nymphs. 
A. Shield as wide as long ... ... ... ... lounsburyi. 
A A. Shield longer than wide ... decoloratus and probably 
australis. 
Larvae. 
A. Coxae I bicuspid, three pairs of stigmatic openings 
australis. 
AA. Coxae I without teeth, four pairs of stigmatic openings. 
decoloratus . 
'*In “ Bericht iiber den XIV Intemationalen Kongress’ fur Hygiene und Demograph.de, ’ 
II, p. 179, appears a paper by JDonitz in which he treats of the ticks transmitting Texas fever 
or red water. He claims that the specimen upon which Karsch founded his genus Margaropus 
was not a monstrosity, as claimed by Neumann, but is in every way identical with the 
species M. Vounsburyi , Neumann. If this is the case, we must then retain the genus 
Boopliilus , our blue ticks becoming B-»>ph.ilns annulatus decoloratus and Boophilus annulatus 
australis , while M. lounsburyi becomes only a synonym of Mai gar opus wrnthemi , Karsch. 
The question now arises as to how this M. wentlienn carne into South Africa from South 
America. Undoubtedly it was brought out some years ago on Argentine horses. 
