CLASSIFICATION AND HABITS OF TIOKS. AT 
Subfamily RHIPICEPHALINZ. 
Genus RHIPICEPHALUS. 
The genera Rhipicephalus and Margaropus (formerly Boophilus) 
are structurally so similar that Neumann and Fuller consider our M. 
annulatus as belonging to the genus Rhipicephalus. All species of 
Rhipicephalus, so far as studied, including five South African forms 
investigated by Lounsbury and one taken by us, drop from the host 
for the purpose of undergoing at least one of the molts. The three 
species placed under Margaropus that have been studied pass both 
molts upon the host. This would seem to supplement the structural 
differences in indicating the generic validity of Margaropus. 
g 
Fig. 3.—Rhipicephalus sp.: Capitulum of female, ventral view. Greatly enlarged (original). 
BROWN DOG TICK. 
(Rhipicephalus sp.) 
Salmon and Stiles in 1901 stated that they were not acquainted 
with any North American species, although they called attention to 
the fact that R. sanguineus had been reported by Neumann from 
Panama, Ff. bursa americanus from Jamaica, and an undetermined 
species from Porto Rico. Banks records an undetermined species 
from Colorado. What appears to be a new species has been taken 
quite generally from dogs in the southern part of Texas and also 
at Tlahualilo, Durango, Mexico (see figs. 3 and 4 and PI. III, fig. 5). 
.@The Arachnida of Colorado. Ann. N. Y. Acad. Sci., Vol. VIII, 1905. 
