302 
canal (Figs. 96 and 98). It is smaller, and much less 
conspicuous, than in the Argasinae , and in the gorged 
female is seen only as a minute pore. 
Lhe Stigmata .—The stigmal plates or peritremes 
(Figs. 96 and 98), into which the tracheal system opens, 
lie behind Coxae IV in the Ixodinae ; between Coxae 
III and IV in the Argasinae. Considerable variation 
a b 
Fig. 98. (A) Dorsal surface of male tick (.Hyalomma ) 
R. — rostrum ; e = eye ; s — stigmatic plate 
{B) Ventral surface of male tick ( Hyalomma ) 
R = rostrum ; C 1 -C 4 = coxae; s = stigma 
A — anus ; g — genital opening 
Scutum and anal plates — black 
exists in the size and shape of these organs in the 
different species and genera. They also differ in many 
cases in the two sexes. 
T he Legs .—The legs consist of six segments, viz., 
coxa, trochanter, femur, tibia, protarsus and tarsus. 
The basal segments, i.e., the coxae, are enlarged and 
